Going into creative mode then back to survival deletes all items from the Large Pack. Have not tested the smaller packs, so not sure if they do the same. This is in Multiplayer.

Full Mod list:
MineFactoryReloaded|CompatExtraBiomes v1.7.10R2.8.0,
BuildCraft|Silicon v6.4.16,
Enchiridion2 v2.0.1,
ProjRed|Expansion v4.6.1.80,
ExtraBees v2.0-pre8,
Torched v4.0.0,
springboards v0.1,
MineFactoryReloaded|CompatTwilightForest v1.7.10R2.8.0,
Botany v2.0-pre8,
MineFactoryReloaded|CompatProjRed v1.7.10R2.8.0,
technom v0.11.0,
BiomesOPlenty v2.1.0,
MineFactoryReloaded|CompatRailcraft v1.7.10R2.8.0,
MineFactoryReloaded|CompatForestry v1.7.10R2.8.0,
ForgeMultipart v1.1.2.334,
RedstoneArsenal v1.7.10R1.1.0,
CoFHCore v1.7.10R3.0.2,
MapWriter v2.1.2,
OpenPeripheral v0.3.1,
ttCore vMC1.7.10-0.1.0-67,
ExtraTrees v2.0-pre8,
MariTech v1.0,
gendustry v1.4.11.89,
BuildCraft|Energy v6.4.16,
IC2 v2.2.726-experimental,
ExtraTiC v1.4.5,
IguanaTweaksTConstruct v1.7.10-2.1.5.140,
FML v7.10.99.99,
Natura v2.2.0,
NEIAddons|Forestry v1.12.8.29,
BiblioWoodsNatura v1.5,
factorization v0.8.94,
CoFH ASM v000
ThermalDynamics v1.7.10R1.0.0,
ProjRed|Illumination v4.6.1.80,
ATG v0.10.0,
TMechworks v0.2.14.100,
fastleafdecay v1.0,
LogisticsPipes v0.8.3.122,
NotEnoughItems v1.0.4.107,
Thaumcraft v4.2.3.5,
Waila v1.5.10,
simplyjetpacks v1.5.1,
appliedenergistics2-core vrv2-stable-3,
NEIAddons v1.12.8.29,
AncientWarfareNpc v2.4.104-beta-MC1.7.10,
factorization.notify v1.0,
BiblioCraft v1.10.4,
BuildCraft|Core v6.4.16,
OpenModsCore v0.7.3,
act v0.0.2a_1.7.10,
SolarExpansion v1.6a,
bdlib v1.8.0.86,
Morph v0.9.1,
MCVanillaTweaks v1.0,
ProjRed|Transmission v4.6.1.80,
Sync v4.0.0,
AncientWarfare v2.4.104-beta-MC1.7.10,
WR-CBE|Logic v1.4.1.9,
MineFactoryReloaded|CompatAtum v1.7.10R2.8.0,
MineFactoryReloaded|CompatAppliedEnergistics v1.7.10R2.8.0,
MobiusCore v1.2.5,
inventorytweaks v1.59-dev-152-cf6e263,
MineFactoryReloaded|CompatBuildCraft v1.7.10R2.8.0,
Morpheus v1.7.10-1.6.4,
endercompass v1.1,
OpenBlocks v1.4.3,
EnderStorage v1.4.7.33,
ForbiddenMagic v1.7.10-0.562,
EnderTech v1.7.10-0.3.2.388,
MineFactoryReloaded|CompatForgeMicroblock v1.7.10R2.8.0,
CarpentersBlocks v3.3.6,
StevesWorkshop v0.5.1,
EnderIO v1.7.10-2.2.8.381,
Translocator v1.1.1.14,
funkylocomotion v1.0,
neiintegration v1.0.9,
Enchiridion v1.1,
CharcoalBlock v1.7.10-1.2,
MrTJPCoreMod v1.0.7.14,
NEIAddons|Botany v1.12.8.29,
Opis v1.2.5,
Tails v1.7.10-1.3.1,
thaumicenergistics v0.8.10.5,
Aroma1997Core v1.0.2.13,
CodeChickenCore v1.0.6.43,
BigReactors v0.4.3A,
MineTweaker3 v3.0.9B,
ThaumicTinkerer-preloader v0.1,
aobd v2.6.2,
AncientWarfareStructure v2.4.104-beta-MC1.7.10,
TravellersGear v1.16.5,
Baubles v1.0.1.10,
ProjRed|Core v4.6.1.80,
denseores v1.0,
FloodLights v0.4.3,
ProjRed|Exploration v4.6.1.80,
Forestry v3.5.6.15,
OpenMods v0.7.3,
BiblioWoodsBoP v1.9,
GalacticraftCore v3.0.12,
runicdungeons v1.1.4,
DeathCounter v4.0.0,
tcnodetracker v1.1.1,
ForgeMicroblock v1.1.2.334,
iChunUtil v4.2.2,
rftools v2.91,
morechisels v1.7.10-1.0-20
PortalGun v4.0.0-beta-4,
ThaumicExploration v0.6.0,
EnderZoo v1.7.10-1.0.11.28,
MagicBees v1.7.10-2.3.1,
InfiniBows v1.3.0 build 20,
ProjRed|Integration v4.6.1.80,
factorization.misc v0.8.94,
McMultipart v1.1.2.334,
Mariculture v1.7.10-1.2.4.2a,
props v2.0.1,
ExtraUtilities v1.2.5,
Micdoodlecore@,
Railcraft v9.6.1.0,
foxlib v1.7.10-0.7.0,
WR-CBE|Addons v1.4.1.9,
IC2NuclearControl v2.2.5a-GoingForTheKill,
ThermalFoundation v1.7.10R1.0.0,
MineFactoryReloaded|CompatVanilla v1.7.10R2.8.0,
headcrumbs v1.5.2,
StevesCarts v2.0.0.b18,
neresources v0.1.0.95,
BiblioWoodsForestry v1.7,
ironchestminecarts v1.0.3,
FastCraft v1.21,
Forge v10.13.3.1428,
Aroma1997sDimension v1.0,
HatStand v4.0.0,
FinndusFillies v2.1.0.12,
ThaumicTinkerer vunspecified,
MineFactoryReloaded|CompatChococraft v1.7.10R2.8.0,
AdvancedSolarPanel v1.7.10-3.5.1,
JABBA v1.2.1,
MineFactoryReloaded|CompatMystcraft v1.7.10R2.8.0,
MineFactoryReloaded|CompatIC2 v1.7.10R2.8.0,
ProjRed|Transportation v4.6.1.80,
AppleCore v1.1.0,
TiCTooltips v1.2.4,
NEIAddons|CraftingTables v1.12.8.29,
NEIAddons|ExNihilo v1.12.8.29,
WailaHarvestability v1.1.2,
Botania vr1.6-190,
Hats v4.0.1,
ProjRed|Compatibility v4.6.1.80,
AncientWarfareNEIPlugin v2.4.104-beta-MC1.7.10,
TConstruct v1.7.10-1.8.5.build957,
factorization.dimensionalSlice v0.8.94,
StevesFactoryManager vA93,
BinnieCore v2.0-pre8,
inpure|core v1.7.10R1.0.0B9,
wawla v1.2.1,
Genetics v2.0-pre8,
mcp v9.05,
Mantle v1.7.10-0.3.2.jenkins184,
journeymap v5.0.1,
appliedenergistics2 vrv2-stable-3,
thaumcraftneiplugin v1.7.10-1.7,
OpenPeripheralIntegration v0.2.2,
MineFactoryReloaded|CompatTConstruct v1.7.10R2.8.0,
AncientWarfareAutomation v2.4.104-beta-MC1.7.10,
DraconicEvolution v1.0.1c,
WR-CBE|Core v1.4.1.9,
harvestcraft v1.7.10g,
ThermalExpansion v1.7.10R4.0.1,
fossil v1.7.10 Build 7.1.0,
TwilightForest v2.3.7,
BuildCraft|Factory v6.4.16,
MineFactoryReloaded|CompatThaumcraft v1.7.10R2.8.0,
GraviSuite v1.7.10-2.0.3,
AgriCraft v1.7.10-1.3.1,
OpenPeripheralCore v1.1.1,
NEIAddons|AppEng v1.12.8.29,
MineFactoryReloaded|CompatSufficientBiomes v1.7.10R2.8.0,
MineFactoryReloaded v1.7.10R2.8.0,
GalacticraftMars v3.0.12,
BuildCraft|Compat v6.4.0,
ComputerCraft v1.73,
AWWayofTime vv1.3.2,
IronChest v6.0.62.742,
MineFactoryReloaded|CompatThermalExpansion v1.7.10R2.8.0,
SpiceOfLife v1.2.3,
ChickenChunks v1.3.4.19,
NetherOres v1.7.10R2.3.0,
debug v1.0,
BuildCraft|Transport v6.4.16,
Emotes v1.0,
Aroma1997CoreHelper v1.0.2.13,
chisel v2.3.10.37,
StevesAddons v0.10.12,
witchery v0.24.1,
BuildCraft|Builders v6.4.16,
MineFactoryReloaded|CompatBackTools v1.7.10R2.8.0,
primitivemobs v1.0

On Server Side only we have,
enetbridge v1.6
FastLeafDecay v1.7.10-1.0