dotnet watch fails with "Unable to apply hot reload due to compilation errors." and no actionable error messages, on a previously working project

`dotnet watch` fails with message "Unable to apply hot reload due to compilation errors." on the first code change, even if it's just spacing changes, with no further errors or information. it always builds successfully on startup and then fails all further updates. this is new in our codebase. this is happening on at least 9.0.304+. It is NOT broken on mac/arm64 for whatever reason.

can't share closed source code but it seems to have started happening on an edit to a long autogenerated enum (2611 elements as of now) (built by a bash script, not any part of the msbuild plumbing, and not actively running during watch scsript) but since it compiles and runs fine in normal builds, and first watch build, i don't think there is anything actually Wrong with that file? Just a potential clue idk.

reverting to sdk 8.0.414 fixes the issue

Searching for the error message brought me to this commit, not sure if it's helpful but it seems to be a recent change?
https://github.com/dotnet/sdk/commit/7bccb4e36a316c421a158b82546b2c5e94cc8ff9