Problem with Dell UP2414Q @ 60hz on MBP running Sierra

After updating my MacBook Pro (Retina, 15-inch, Late 2013) to Sierra, my UP2414Q stopped working at 60hz when used with a P2415Q.

I know this is a very edge case, but if you're using a UP2414Q and P2415Q with a MacBook the update to Sierra will mean that you have to disable DP 1.2 on the Dell UP2414Q. On El Capitan, it worked fine. Interestingly 2 x P2415Q will work fine simultaneously @60hz.

I hope this helps someone or is picked up and a fix is put into the next Sierra update.