Help with mode conflicts

In this project there are only local variables. There are no layers or objects in the file, therefore nothing assigned color variables. There are no libraries added to the file. Yet there is somehow a conflict.

How is this possible? Is it possible to find the source of the conflict? With nothing in the file it doesn’t make sense to me.

Is there a plugin that can find the source of mode conflicts? As natively there is little to no useful information provided. Thank you!