Can confirm this seems to be a problem with live coding. I can’t quite figure out what is causing it or when it happens. Unreal 5.0.3.
One thing I’ve noted is that sometimes the files in C++ Classes/MyProjectName/ will just disappear from the content browser, but only some of them.
I can confirm they still exist by right-clicking the content browser and “show in explorer”.
I need to turn off “show C++ classes” in the content browser, turn it back on again, then they appear again.
However this doesn’t fix the missing blueprint parent issue. It seems the only way around this is to not use live coding, for me at least.