App Designer Syntax Errors When Saving and Reopening .mlapp File

I have been having a problem with tons of syntax errors showing up when saving and reopening apps in App Designer. When I save the file, there are 0 errors, but, when I open it again to continue working on it, there are new components added and a bunch of syntax errors. This has made it impossible to work on an app over multiple sessions.

I tried searching for an answer to this, but wasn't able to find anything relevant. This is with MATLAB R2020a.

[dpb]

Not used R2020A but not seen issue w/ R2020b nor earlier releases prior to that (R2019b is probably first for which I actually ever used App Designer, though).

Have you checked for updates just in case there was some glitch that got fixed? I'd think unlikely, but...or, can you upgrade to newer release? Not sure if there's a way to just reinstall only App Designer; I think probably not; the download and install does keep getting bigger and bigger and bigger...

Does this happen with every new instance--if you just start a new app with just one pushbutton, say, will it happen if you close and reopen it? If that were the case and have latest patches for your release, I'd say it's worthy of a support request.

ADDENDUM

Oh. Is this a new symptom or has it always done this from initial use?

[David Archer]

This was from initial use (though I have only had this installation ~1 year).

These errors were happening if I closed app designer and reopened, without closing Matlab completely. I noticed that the errors don't occur if I close all of Matlab, then restart and open App Designer.

The above may be moot, because I updated the latest patch and these errors no longer occur. That probably should have been my first step before posting... so I appreciate your suggestion. If it happens again though, I will update this post.

Thank you!