So... There is really somethings strange is going on with the server's RAM. I'll fix it.

But is there any way to fix the save?

Yeah, this can be true. I'll check it now...

using ubuntu linux & factorio_headless_x64_1.1.80 on version 1.85 the same.
server with settings:
"autosave-interval": 5,
"autosave-slots": 20,
"auto_pause": false,
So there is no previous "normal" saves
yesterday we disconnected from server and today morning server work "fine" but when i try to ...