Perhaps the issue is because of something that is happening on the server side. That I can't determine. However, even after opening chests, then closing them to see if ChestTracker show the contents, it may not when I come back. This app is so helpful when it works for me, so I am hoping that the issue can be resolved. It has saved

• I am using a pc running Microsoft Windows 10 Pro, version 10.0.19045 build 19045.
• I am using Fabric Loader version 0.15.9-1.20.4
• I am playing on a Java Server

Couple things I can think of:

• You're on a multiworld-type server (one with a hub or multiple overworlds) - the mod might be mixing two overworld-looking levels for example, as theres not an easy way to check on the client side. Improvements tba
• A decent amount of time has passed - by default, the mod clears memories over a certain age to keep the fresh ones (think long distance ones you've seen once like buried treasure). You can extend or disable this under integrity settings for that memory bank:

I also experience it!
I have memory lifetime set to never expire and i play on the exact same vanilla server and sometimes Chesttracker just forgets the content of some containers.

ChestTracker always forgets chest contents after a major version upgrade - is there any way to backup/restore between versions? i have about 900 containers that it's really annoying to have to go re-poll after an upgrade :/