After running a few more dungeons, I've only had threat issues with a scaled down bard. Thinking back, my original issue was also with a few scaled down bards.

Opening with Toma -> Butcher's Block combo x2 and as I finish the second or right before it, there's a bard getting his nose chewed on.

I could just be running into Bards that have no concept of throttling against a leveling tank or something could be off else where. They did seem to hesitate on the pull but, who knows after that.