@NZsimm3rThat is unfortunate.
I have something of a work-around in place:
1) Make a backup copy of your -entire- Saves directory without the sub-directories before you play, and especially before you save!
2) ESC and Save As in Sims 4. Save your file under a new name, but do not exit the save menu!
3) Save As again and look to see if the correct filename saved. In my experience it usually takes two or three attempts before it actually *saves* under the name you give it - the other times it overwrites one of your old save files at random. Keep doing this until your Save As finally "takes".
4) Exit Sims 4.
5) Order the Sims 4 Saves directory by creation date and -move- (don't copy) all of the files that are time-stamped during the time you were saving the game. If you had to save three times to finally get the save file to save correctly, there should be 3 files.
6) Copy the saves from the backup you made before gameplay. When the file system asks you about duplicates, skip all of those. We just deleted the overwritten files and the one correctly saved file. We want to restore the ones that got overwritten.
7) Copy the saves from where you -moved- the recent 2 or 3 save files. Again, skip all duplicates. This should then copy the legitimate file you just made back into your Saves directory.
It's a colossal pain, but if you're careful it should work. I will be doing this on a daily basis instead of *every* time I save. So, I might make 5 incremental saves in a 3-hour gameplay period. Maybe it took 9 tries total to get the files to "stick". I will then follow my little routine but just look at the files created *today*.
Thanks for the link - I'll go take a look over there and see if there's anything I can learn or add.