I’m not sure what’s up, but entries have certainly been removed. This was then: https://web.archive.org/web/20231019235547/https://lemmy.world/modlog
This was a more recent IWM archive: https://web.archive.org/web/20231021224842/https://lemmy.world/modlog
Search for “HEISENBERG” in both and then read back through to the most recent to get an idea of how different they are. Some bans are showing up, some aren’t, a lot of them aren’t even there.
I’m no expert, but modlog isn’t exactly the same across all instances. I think actions like a user getting banned in their home instance do get propagated to the other modlogs, since my ban got propagated to lemmy.ml’s moglog, but this user’s ban in lemmy.world wasn’t.
I haven’t touched the lemmy code, but seeing what’s mentioned over at https://github.com/LemmyNet/lemmy/issues/2349 , the modlog seems to be just a combination of database tables that are normally maintained server side but, just like in any other database, can be edited manually.
Only trust the modlog as much as you trust the server you are reading it on.