ENUMs inexplicably turned into bytes?

Yes, actual variable type changed.

I can’t say if standard ENUMs would be unaffected as I was only using custom ENUMs, and unfortunately did not think to check inherited standard ones.

It was only ENUMs in two blueprints that failed to compile, but it was all custom ENUMs in those two blueprints.

Oddly I have same type of ENUM variables in several other blueprints(that interact with two that failed), but their variable types were not changed.
I also have several more blueprints with a whole different set of custom ENUMs that were also unchanged and fine.

Yes, after fixing them they remained fixed after reopening project.

only other details I can recall, atm, is that custom ENUMs were declared in C++ and are apart of a custom structure also declared in C++.

If I remember anything else I will post here.
I will also try to remember to check output log first thing if it occurs again.