I had a hopper facing the side of a furnace (fuel input) and accidentally sent a bundle into the hopper via the inventory. The bundle then emptied and all the items got deleted. They didn't pass through to the furnace as the fuel slot was already full.
Linked issues
duplicates 1
Comments 2
This is fixed in the 1.21.110.25 Preview:
Fixed a bug where putting items in a Bundle as it is being transferred from one Hopper to another would delete the item
Adding: on Realms, latest version of Bedrock