Microsoft Technologies based on the .NET software framework. Miscellaneous topics that do not fit into specific categories.
This issue had been ongoing, and a fix released in VS 17.12.
In short (as I understand it), the real-time parser scheduler had a bug where it delayed file review if a user started editing it, but the follow-up review was never scheduled. Hence, when deleting the "obj" and "bin" folder would cause the parser to restart and with non-edit conditions, those phantom errors would disappear.
The real-time is different than the compiler ops so the "errors" appeared in the error list, but the application would compile/run fine. The team found and tested a fix and released it in 17.12; including WPF & MAUI.
Release Notes: https://learn.microsoft.com/en-us/visualstudio/releases/2022/release-notes
Reported Issue: https://developercommunity.visualstudio.com/t/Second-time-reporting:-WPF:-C-Editor-ca/10532548