Not saving file

I save on a consistent basis. Over the last 6 months or so, I have had crashes where it seemed the file has not been saved. At first I thought I must have simply not saved when I thought I had, but I paid particular attention and established for sure they weren’t happening. Also, sometimes the auto saved seemed not to be as recent as I would have expected, but on other occasions was within minutes prior to the crash - so I wasn’t sure on that one. I am a mild tempered bloke, but today I absolutely lost it! Had a crash, and thought no problem, as I had been saving regularly, as the work was very tedious, and I noticed auto save kicking in at regular intervals. BUT the “recovered” file was about 2 hours back! Anybody guess what’s going on?