Well, obviously, it isn't turning itself off, but something (a command, or 3rd party app, etc.) is doing it.
Use the lisp code found here to monitor the SAVETIME system variable, and when it changes, you'll have a good idea of what did it.
One solution is to create a wrapper for a common command, and just set SAVETIME there.
.... Autosave is pretty import?
Turned it off last century - I don't allow my students to rely on autosave for anything.
They learn that saving is their responsibility.
Loss of a file is no excuse for any reason in my class.
Why I concur that students shouldn't rely on autosave, turning it off seems unnecessarily severe. That does in-effect, disable the drawing recovery manager. I can't imagine that once trained to save regularly that businesses would want drafters turning off autosave just to prove how good they are. The would be foregoing the advantages built into the software.
I save frequently but have also benefitted from the occasional drawing recovery process.
Several of the other CAD programs we use don't even have AutoSave (including Autodesk Inventor) and CAD products from other companies. There are actually some negative implications to AutoSave that have been discussed here and other CAD forums over the years. Bottom line (IMO) it is the operators responsibility.
Nearly every time I hear about AutoSave "not saving" it is by someone who worked for several hours without saving and just lost all their work.
You should never lose more work than you are willing to recreate without too much effort. In more than 26 years of CAD work I have never relied on AutoSave.