12M Auto - New attachments are unlocking, but previous ones are still locked

On the 12M Auto, I'm currently Mastery 6, and new attachments are unlocking without a problem.

However both the XDR Holo and the Laser Sight are both still locked. 

This has been going on for a good couple of weeks, and nothing I can do in-game seems to fix it. 

Observed Behaviour

New attachments for the 12M Auto are unlocking, but the XDR Holo and the Laser Sight remain locked and unselectable.

Expected Behaviour

For the XDR Holo and the Laser Sight to be selectable as the requirements for unlocking them have been met.

How to Recreate

Obviously I can't retest this myself, but I've got a hunch that the end of level unlock screen where you can automatically add it to your loadout may have something to do with this bug.

The reason I say this is because when I unlocked one of the magazines from Mastery 4 or 5, I can't remember which, I chose to automatically add it to the loadout, but then it locked it out, and I couldn't select it. 
However when I switched game modes, the game randomly reset all the attachments and they were removed. That previously locked magazine could then be added as an attachment. Although the Holo and Laser sight were still locked.

So if you were going to retest it, you could start there. Try achieving the requirements for the unlock, and choose to automatically add it to your loadout. Try it with no attachment slots available, as I've also got a hunch that that's how the bug manifests.