Glue not generating on engine upgrade or enabling engine plugins
When upgrading to a new engine version or enabling an engine plugin, UnrealBuildTool doesn't trigger because it doesn't detect any source code changes, and no new glue will be generated.
To fix this you need to force a glue re-generation by manually deleting the Intermediate and Saved folders in the UnrealSharp plugin folder.
Now compile as usual, and the glue will be re-generated.