I've been noticing some items have dissapeared randomly in my backpack, today it was totally obvious it wasn't me just forgetting as i had two stacks of ancient debris and i put them in the furnace, later i opened the backpack again and the two stacks were still there as well as in the furnace, i have no clue what's causing this but here's the modlist of the server:

Data Packs

file/AllTheMons x Mega Showdown [v2.7].zip (world)

file/BCA-Datapack-3.8_CE_Cobbledollars_M1.21.1_C1.6.1 .zip (world)

file/Player Graves.zip (world)

file/Bedrock Impaling.zip (world)