It started with 1.2.6 and would quickly get stuck in under 30 min. Tried 1.2.6d before the first comment, and it did take a lot longer (>1hr) but Darian did start doing the "X (unit of time) later" thing and wouldn't stop.
Try setting shortTermMemoryClearingEnabled to true in AppData\LocalLow\Three Eyes Software\Silverpine\settings.json and waiting at least 12 ingame hours after. It eliminates these kinds of issues, but it's turned off by default because it reduces character consistency. If it wasn't a problem before, it's because Nemo was paying less attention to things, including any repetitive behaviors.
Was able to go for quite a while without Nemo ever doing any of those annoying things. The character consistency was noticeably worse but at least the conversations weren't getting derailed because someone mentioned a number or the passage of time.
Now if only I could figure out how to get the AI to have the character actually follow me instead of role-playing that they're following me.
I had Rosalyn eventually start counting with "shortTermMemoryClearingEnabled" set to true, this was after about an hour within the same dialogue "session" without any turns passing in game. Waiting for at least 12 hours ingame cleared things out and she stopped counting, but she quickly started just repeating herself verbatim. Turning the setting to false, just has Rosalyn continue counting even if you wait. Which sounds like the expected outcome if the problem has to do with the AI model's short term memory.
As an experiment, try setting koboldUrl in settings.json to: https://github.com/LostRuins/koboldcpp/releases/download/v1.81.1/koboldcpp.exe
I assume the long-term memory is also poisoned if this has been going on for a while.
I realized I left out some important info, I frequently start over and swap out whichever character I'm playing by swapping the save files out. So, most times I've run into the memory poisoning have been on fresh starts, but if there's any data that the AI uses outside of those save files, I could be the one causing the poisoning by swapping around saves or starting fresh.
I did as you asked and downgraded koboldcpp, on a save that started on 1.2.6d and had gotten memory poisoned with shortTermMemoryClearing set to true. It had an interesting effect.
Rosalyn started reading from WorldLore.md. I realized that I had forgotten to wait 12 ingame hours, so I decide to see what would happen if I did. After the wait, Rosalyn had gone back to normal but did eventually start doing the "x (unit of time) later..." again. After waiting at least 12 ingame hours from that point, Rosalyn went back to timestamping on the second response.
After playing around for a while, it seems that numbers are the biggest cause of the memory poisoning issue. If Nemo tries to quantify something, it'll get stuck with that data. On top of that, with "sTMCE" set to true, the model seems to get more stable as I go forward. I'll have to wait 12hrs ingame to clear the memory once it gets poisoned, but after a few times it seems the model picks up on the fact that something is going wrong, and is either "fixing" itself for that save or just avoiding whatever's causing the issue.