Compile: Kindle Supported File Type won't switch off

I have 2 compile settings in a project - one for eBook and one for paperback. The eBook one has 2 supported file types (pub and Kindle) and I want the paperback setting to only support pdf and docx.

My problem is that the paperback includes Kindle as a file type and no matter how many times I deselect that option and save, it keeps coming back at me.

What do I need to do to get rid of this? My paranoid self thinks this is the reason I keep altering the compile settings for ebook whenever I make changes to my paperback settings, but I acknowledge I’m not too sure what I’m doing as I tweak my way to a finished version.

TIA

Graeme