Adding an empty code class to a Blueprint-only project prevents the project from being able to perform any hot reloads. When clicking the Compile button in the Editor, a warning is added to the log that states "Warning: RebindPackages not possible (no packages specified)"
No hot reload occurs, and the Output Log shows the following message: Warning: RebindPackages not possible (no packages specified)
A hot reload is performed.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-69755 in the post.