Part freezes following insertion into assembly and adding a coincident constraint to axis

Never before seen this. I have an assembly consisting of multiple instances of two different parts. The parts are constrained by using the coincident feature on the axes of the two different parts. There is no indication in the feature menu regarding other constraints on the part. I've deleted some previously mated parts then reinserted them but this time with the same problem.

The problem is that when the new part is assigned a single constraint to the assembly, it becomes frozen - unmovable but no other constraint indications,

When I saved and closed the file then came back later and I reopened the assembly file. I had a dialog box that mentioned a rolled back feature so I said yes to continue. That's where the problem began.
When I remove the new constraint, the part floats as usual and can mate to other parts but the problem only exists when attaching to the assembly with any mate, flush Coincident or otherwise.

I have other similar assemblies and the problem is nonexistent there.