I've been running three displays successfully since 10.9 - two TB->DP and 1 HDMI->DVI. After the update to 10.10.2 only two displays are recognized when all three cables are plugged in. However when only two displays are connected - in any combination - both are detected, so it seems the ports are working properly just not with all three plugged in. No applications are running (or on auto-start) that have anything to do with display except BetterSnapTool.
Is there a way to re-enable the ability to have 3 displays?
MacBook Pro with Retina display, OS X Yosemite (10.10.2), Late 2013