Field settings for content types don't save in certain cases

I have a field in a content type that I do not wish to display. I drag the field into the Disabled section, but the settings won't save.

I can disable the label and the link to the entity (it's a taxonomy field) and it saves OK. But once I drag it into the Disabled section and save, it reverts.

This is regardless of whether I'm editing from the master domain or from the sub.

Very reproducible. Thoughts? Thanks!