Just updated to 10.12.4 on my 2013 6-core Mac Pro with D700s and 64 GB RAM. I have two 30" monitors. The resolution of one of the monitors, a Dell U3011 connected with displayport, is now being limited to 1080P max and not the native 2560 X 1600. Rebooted several times with no change. Never had this problem before. Any one else with this unacceptable problem?