Illegal use of reserved keyword "classdef" when trying to continue debugging

I've been getting this odd error a few times recently that I never had before when trying to use F5 to continue debugging my code:

I run some code (this happens to be from a UI so the first breakpoints are in App Designer, but behaviour is the same both there and here, in the normal editor on a later breakpoint), hit a breakpoint, see what I want to see or try something on command line, then I hit F5 to continue debugging. This is what I have done for the whole time I've used Matlab (almost 20 years), yet now I keep getting this error. Does anyone else get this? It's only started happening since R2025b

Some obvious things I already know and have checked:

• My F5 shortcut is still set as normal:

• I'm aware, of course, that trying to run a class file using F5 often leads to errors, but here I am clearly in debug mode, in a breakpoint (also shown by the K>> on command line) so it should interpret F5 as 'Continue', not as 'Run', as it always has in the past.
• F10 to 'Step' still works as expected, as does clicking the green arrows to Continue (which also shows the F5 shortcut in the tooltip when I hover over it).
• It's not specifically this line of code. I covered the rest of the code as I can't share it, but it also happens, for example, if I do F10 once, then am on the 'end' statement of the function and press F5 again, or basically anywhere else in this debug session that the code lands.

I suspect this is just the latest in a long line of issues I am having with App Designer not being properly in sync and generally being unusable at times, even though it is in the main Editor too, the first breakpoint was in an App.

[Steven Lord]

Look in the upper-right corner of the editor window. Do you see a little colored square there? If you do, what color is it? If it's red, did you modify the class file (or another class file that's being called later in your code) in some way that makes it no longer a valid MATLAB class file?

[Adam]

There's a green tick, no errors, in both this and the 2 App Designer files further up the call stack, and all the relevent files are saved too, with no pending changes.

[Adam]

This does look like another bug that probably stems from App Designer, even though I was in the regular Editor. Even after I clicked Stop Debugging, and now my Command Window prompt is >> rather then K>> and the Editor green button now says Run rather than Continue, and the Red Stop button is disabled I still have the green arrow in my editor on the line I was debugging at when I stopped it so it is clearly just confused as to what state it is in.

I guess I'll have to send a tech support request in, but I've sent so many in about App Designer issues that are very hard to repeat it hardly seems worth it as I know what the response will be!