Ok, so been testing a little over the last 11 days regarding the 'sudden scenario restart' issue, and can pretty much say it's 100% related to the Dictionary. Worlds with larger dictionaries suddenly reset FAR sooner than those with smaller ones, and the ones that doesn't have one doesn't reset at all. Increasing context length as mentioned in an earlier post makes it last longer before it happens, but unless context length end up being much larger than Max Memory, it seems inevitable to happen eventually.
Not sure what can be done about it though. If I remember right, the dictionary was designed as a way to go beyond context limit, but apparently it didn't work as expected.