I had the exact same problem. i think i've figured out the problem, and it's a doozy.
in the options, it gives you a max number of autosaves. by default it's set to 25, and i didn't touch it. In my instance of losing 2+ hours i had also been making manual saves but hadn't kept up with them since the game had been autosaving. And then i wiped and my last autosave was 2+ hours ago. i looked and my autosaves stopped at around the 20's. including my manual saves that makes about 25 "Saves" (but not autosaves).
When you hit your maximum number of autosaves, that's it. There is no warning, and the game doesn't seem to overwrite the oldest autosaves. And that's the whole problem. if you manually delete old autosaves the game will start autosaving again but unless you manually delete the autosaves, the game just stops autosaving. there is also no way to set unlimited autosaves. What needs to be done is the game needs to overwrite the oldest autosaves, that's literally it. if it did that you could only have 5 autosaves but it would properly keep saving. Until the fix the autosave problem i suggest just keep manually saving all the time
