Adding my voice into the mix, I am also experiencing these issues. Re-generating the project files works for about 2 minutes, but by the time it’s rebuilt the intellisense database my code is back to red squiggle land.
Mine seems to specify the error comes from the class definitions.
EDIT: It also appears to mostly only affect Actor files. My function library and static enum classes seem to work completely fine in the .cpp files, but display errors in the .h files.