Prototypes and "Basic Piece"

While beginning to look over one of my modules to update it to 3.7beta4, I came across an interesting issue…

One of my Prototypes includes “Basic Piece”… Looking at other Prototypes, they do NOT include “Basic Piece.”

Note that REMOVE is greyed out, as are the ability to move the trait up/down/top/bottom

In looking at other Prototypes that do NOT include “Basic Piece” (most of them), I further note that the option to include this as a trait (from the long list on left) doesn’t even exist (“Basic Name” exists - but not “Basic Piece”).

Anyone have any ideas on what is going on here?

I’m guessing I should delete the Prototypes w/ “Basic Piece” trait and recreate them…?

Yes, it definitely should not be there. Have seen this happen before and never been able to track down why.