Mr Robot wants me to use Revolving Blades on my helmet when I am a tank. Revolving Blades is not available to be chosen in Vengeance spec. I have taken Rigid Carapace as it is one of the top 2 traits for survivability. This seems to be a bug with Mr Robot.
That’s most likely not a bug in AMR but just an incorrect setting on your side. AMR uses a priority system for specs which you can see and change to the left of your currently equipped items.
I’d guess you currently have Havoc as priority #1 and Vengeance as priority #2 which will cause AMR to first optimize for Havoc and not change enhancements for those items for a lower priority spec (i.e. Vengeance) as it is not feasible to switch around traits every time you change specs.
You can just drag and drop Vengeance to the top if you want to assign a higher priority to that spec.