0. ALWAYS PROVIDE INFORMATION ABOUT MODLOADER (Fabric / Forge) AND MOD VERSION (For Example 1.19.2-8.2.10)
   Fabric 0.16.13
   Traveler's Backpack 10.1.18
   9999 stack size

1. Describe the bug
   with 9999 stack size, when I put in a stack that has more than 99 items, I get a crash as soon as I pause the game (log and crash report included below). I had two stacks: dark oak logs, which I have 211 of, and copper, which I have 124 of.

2. Write steps to reproduce the bug
   Get a backpack
   put a stack of more than 99 inside it
   pause the game
   it crashes

3. What is expected behavior
   It shouldn't crash :v

4. Screenshots (If applicable)
   Log: https://mclo.gs/D0hbGS7
   Crash report: https://mclo.gs/WdY5OAV

It also just did it randomly the first time, here's the second log of when I intentionally tried to crash: https://mclo.gs/8gqH1oY

Here's the list of all the mods I have, I have a lot.
Additional RPG Jewelry [2.0.5-1.21.1]
AddonsLib [1.21.1-1.7]
Alloy Forgery [2.4.1+1.21]
Almanac [1.0.2]
Alternate Current [1.9.0]
AmbientSounds [6.1.8]
Amendments [1.21-1.2.24]
AppleSkin [3.0.6+mc1.21]
Architectury [13.0.6]
AttributeFix [21.1.2]
AzureLib Armor [3.0.5]
Bad Wither No Cookie Reloaded [3.20.2]
BadOptimizations [2.2.1]
Battlemages [0.0.8-1.21.1]
Better Advancements [0.4.3.21]
Better Beds [1.4.0]
Better Biome Reblend [1.5.2]
Better Combat [2.1.3+1.21.1]
Better Statistics Screen [3.13.9+fabric-1.21]
BetterF3 [11.0.3]
BetterGrassify [1.6.0+fabric.1.21.1]
BetterSafeBed [1.21-16]
BetterThanMending [2.2.0]
BiomesOPlenty [21.1.0.7]
Blood Mages [0.0.8-1.21.1]
Bookshelf [21.1.56]
Bosses of Mass Destruction (Beta) [1.10.2-1.21.1]
Brewin' And Chewin' [4.2.5]
Bundle API [1.0.4]
CIT Resewn [1.2.2+1.21]
Cardinal Components API [6.1.2]
Charm of Undying [9.1.0+1.21.1]
ChoiceTheorem's Overhauled Village [3.5.7a]
Cinderscapes [5.0.2]
Cliff Face [2.0]
Cloth Config v15 [15.0.140]
Clumps [19.0.0.1]
Collective [8.1]
Concurrent Chunk Management Engine [0.3.0+alpha.0.319+1.21.1]
Continuity [3.0.0+1.21]
CreativeCore [2.13.1]
Debugify [1.21.1+1.0]
Dragon Scale Mod [0.0.2-1.21.1]
Dragonsteel Mod [0.0.3-1.21.1]
EMI [1.1.21+1.21.1+fabric]
EMI Enchanting [0.1.2+1.21]
EMI Loot [0.7.5+1.21+fabric]
EMI Ores [1.2+1.21.1+fabric]
EMI Professions [1.0.3]
Easy Anvils [21.1.0]
Easy Shulker Boxes [21.1.2]
Eating Animation [1.21+1.9.72]
Effortless Structure [3.4.0]
Elemental Metals [0.0.4-1.21.1]
Elemental Wizards (RPG Class) [2.3.1-1.21.1]
Elytra Slot [9.0.1+1.21.1]
Enchanting Infuser [21.1.0]
End's Delight [2.5.2+refabricated.1.21.1]
Enhanced Block Entities [0.10.2+1.21]
Entity Model Features [2.4.1]
Entity Sound Features [0.4]
Entity Texture Features [6.2.9]
Euphoria Patcher [1.5.2-r5.4-fabric]
Extra Mod Integrations [1.0.2+1.21.1]
Fabric API [0.115.4+1.21.1]
Fabric Language Kotlin [1.13.2+kotlin.2.1.20]
Fallen Paladins and Priests [2.2.5-1.21.1]
Fallen Wizards [0.1.8-1.21.1]
FallingTree [1.21.1.7]
Fancy Delight [1.0.0]
Farmer's Cutting: Biomes O' Plenty [1.21-2.0.0-fabric]
Farmer's Cutting: Cinderscapes [1.21.1-1.0]
Farmer's Cutting: Regions Unexplored [1.21.1-1.1a-fabric]
Farmer's Delight [1.21.1-3.0.1+refabricated]
Fast Paintings [1.21-1.2.15]
FastQuit [3.0.0+1.20.6]
Faster Random [5.1.0]
FerriteCore [7.0.2-hotfix]
FeyTweaks [1.21-1.2.8]
Fix Keyboard on Linux [1.0.1]
Forge Config API Port [21.1.3]
FrozenLib [2.0.4-mc1.21.1]
Fusion [1.2.7]
Fzzy Config [0.6.9+1.21]
GPU Tape [1.0.5.1]
Gazebos (RPG Series) [2.0.3+1.21.1]
GeckoLib 4 [4.7.5.1]
GlitchCore [2.1.0.0]
Head In The Clouds [1.1.0]
HopoBetterMineshaft [1.3.0]
HopoBetterRuinedPortals [1.4.4]
HopoBetterUnderwaterRuins [1.2.1]
ImmediatelyFast [1.6.5+1.21.1]
Immersive Thunder [1.21.1+1.2.2]
Incendium [5.4.3]
Iris [1.8.8+mc1.21.1]
ItemSwapper [0.7.8.1]
Jade [15.10.0+fabric]
Jade Addons [6.0.3+fabric]
JamLib [1.3.2+1.21.1]
Jewelry (RPG Series) [2.0.7+1.21.1]
Just Enough Breeding [1.5.0]
Just Hammers [21.1.0]
Language Reload [1.7.3+1.21.1]
Let Me Despawn [1.5.0]
Lighty [3.0.0-beta.8]
Lithium [0.15.0+mc1.21.1]
Lithostitched [1.4.2]
Log Begone [1.0.3]
MC-258859 [1.0]
Macaw's Biomes O' Plenty [1.21.1-1.2]
Macaw's Bridges [3.0.0]
Macaw's Doors [1.1.2]
Macaw's Fences and Walls [1.2.0]
Macaw's Lights and Lamps [1.1.1]
Macaw's Paintings [1.0.5]
Macaw's Paths and Pavings [1.1.0]
Macaw's Roofs [2.3.1]
Macaw's Stairs and Balconies [1.0.1]
Macaw's Trapdoors [1.1.4]
Macaw's Windows [2.3.2]
MidnightLib [1.6.9]
MixinTrace [1.1.1+1.17]
Mod Menu [11.0.3]
ModernFix [5.21.0+mc1.21.1]
Moonlight Lib [1.21-2.18.5]
More Craftings of Runes [0.0.2-1.21.1]
More Culling [1.0.6]
More Delight [25.03.27-1.21-fabric]
More RPG Classes [2.1.1-1.21.1]
More Runes [0.0.2-1.21.1]
More Spell Attributes [0.0.7-1.21.1]
Mouse Tweaks [2.26]
My Nether's Delight [1.21.1-2.0.3+1.7.8.refabricated]
Mythic Metals [0.22.2+1.21]
Mythic Metals Decorations [0.8.2+1.21]
Nature's Compass [1.21.1-2.2.7-fabric]
Nemo's Better Mending [1.1.1-1.21.1]
Nemo's Woodcutter [1.12.3-1.21.1]
Noisium [2.3.0+mc1.21-1.21.1]
Ocean's Delight [fdrf-fabric-1.0.2-1.21]
Oh The Trees You'll Grow [5.0.10]
Paladin's Furniture [1.4.2]
Paladins & Priests (RPG Series) [2.3.1+1.21.1]
Particle Rain [3.0.5]
Placeholder API [2.4.2+1.21]
Player Animator [2.0.1+1.21.1]
Presence Footsteps [1.11.0+1.21]
PrickleMC [21.1.6]
Puzzles Lib [21.1.33]
RangedWeaponAPI [2.0.5+1.21.1]
Reactive Music [1.0.3+1.21]
Realistic Bees [4.2]
Rechiseled [1.1.6+b]
Reese's Sodium Options [1.8.3+mc1.21.4]
Regions Unexplored [0.5.6.1]
Reinforced Chests [3.1.1+1.21.1]
Remove Reloading Screen [5.0.10+mc1.21.1-fabric]
Repurposed Structures [7.5.13+1.21.1-fabric]
Repurposed Structures - Farmer's Delight Compat [7]
Resourcefulconfig [3.0.10]
Resourcify [1.7.1]
Right Click Harvest [4.5.3+1.21.1]
Roguelike Dungeons [2.0.8-1.21-fabric]
Rogues & Warriors (RPG Series) [2.3.0+1.21.1]
Runes [1.1.2+1.21.1]
Rustic Delight [1.4.0]
ScalableLux [0.1.0+fabric.26c6e72]
Scorched [1.1.4a]
Searchables [1.0.2]
Shield API [2.0.2+1.21.1]
Silk (All modules) [1.10.7]
Smarter Farmers [1.21-2.2.2]
Sodium [0.6.13+mc1.21.1]
Sodium Dynamic Lights [1.0.9]
Sodium Extras [1.0.7]
Sodium Leaf Culling [1.0.1]
Sodium Options API [1.0.10]
Sodium Options Mod Compat [1.0.0]
Sodium Shadowy Path Blocks [4.0.0]
Sound Physics Remastered [1.21.1-1.4.12]
Spanish Delight Refabricated [1.0.3]
Spell Engine [1.4.2+1.21.1]
Spell Power Attribute [1.2.3+1.21.1]
Stack Refill [4.6]
StackDeobfuscator [1.4.3+08e71cc]
Stellarity [3.0.6]
Stoneworks [21.1.0]
Storage Delight [25.03.09-1.21-fabric]
Structure Layout Optimizer [1.0.10]
Structure Pool API [1.1.3+1.21.1]
SuperMartijn642's Config Library [1.1.8]
SuperMartijn642's Core Lib [1.1.18+a]
Supplementaries [1.21-3.1.4]
Supplementaries Squared [1.21-1.2.8]
TCD Commons API [3.12.7+fabric-1.21]
Tectonic [2.4.3]
TerraBlender [4.1.0.8]
TerraBlenderFix [0.0.1]
The Ancient Trinkets Index [0.1.1-1.21.1]
The Archaic Artifacts Catalogue [0.0.3-1.21.1]
The Cursed Trinket Index [0.0.8-1.21.1]
The Dark Artifacts Catalogue [0.0.2-1.21.1]
The Great Alchemical Compendium Mod [4.0.4-1.21.1]
The Secret Alchemical Parchment [0.0.1-1.21.1]
ThreadTweak [0.1.5+mc1.21.1]
Trail&Tales Delight [1.1.5]
Trailier Tales [1.1.4-mc1.21.1]
Traveler's Backpack [10.1.18]
Trinkets [3.10.0]
TxniLib [1.0.23]
Universal Bone Meal [21.1.0]
Universal Enchants [21.1.5]
Vanilla* Horses [1.0.2+1.21.1]
Vegan Delight [1.4.1]
Veinminer [2.4.2]
Veinminer Enchantment [2.2.2]
Very Many Players [0.2.0+beta.7.171+1.21.1]
Village Taverns (RPG Series) [1.0.3+1.21.1]
Visual Workbench [21.1.0]
Visuality [0.7.7+1.21]
Wakes [0.4.1+1.21.1]
Wizards (RPG Series) [2.3.3+1.21.1]
Woodlands: The Core [1.21.1-1.2.2]
Xaero's Minimap [25.2.0]
Xaero's World Map [1.39.4]
YUNG's API [1.21.1-Fabric-5.1.4]
YUNG's Better Desert Temples [1.21.1-Fabric-4.1.5]
YUNG's Better Dungeons [1.21.1-Fabric-5.1.4]
YUNG's Better Jungle Temples [1.21.1-Fabric-3.1.2]
YUNG's Better Mineshafts [1.21.1-Fabric-5.1.1]
YUNG's Better Nether Fortresses [1.21.1-Fabric-3.1.4]
YUNG's Better Ocean Monuments [1.21.1-Fabric-4.1.2]
YUNG's Better Witch Huts [1.21.1-Fabric-4.1.1]
YUNG's Extras [1.21.1-Fabric-5.1.1]
Yeetus Experimentus [87.0.0]
YetAnotherConfigLib [3.6.6+1.21.1-fabric]
Zoomify [2.14.2+1.21.1]
oωo [0.12.15.1+1.21]
spark [1.10.109]
stack [1.0.3]

Not really issue on my side, trinkets' fault here

Ah, I'll link this post to them then.

Just wanted to say while I'm here, thanks for all your hard work on the mod!

Just wanted to say while I'm here, thanks for all your hard work on the mod!

Thank you!

Update: the problem was the stack size mod. The only one that works is Stackable, which does not, in fact, crash when I put stuff in a backpack. Hurray for Stackable! :D