Additional file change doesn't trigger source generator and recompile in Editor

I have the following setup:
A source generator generates a partial struct with data from a json file that is provided with the “-additionalfile” keyword through csc.rsp.

Changes to the json file are reflected in the IDE (Rider) where the source generator is immediately triggered and updated with new data but this is not happening in Unity.

The bug here, a change to an additional file should trigger a recompile of the assembly but nothing is happening. The source generator will only run on the new updated file when you trigger a recompile manually. (adding a space or new line in some code file)

As a workaround, I use a .cs file now instead of a .json as the additional file input but that’s obviously not very nice.

Can this be fixed? Should I add a bug report or will it just end up in a won’t fix because CoreCLR is coming eventually?