I haven't read about anyone else experiencing this issue yet, but:
After spending several hours customizing my UI yesterday I noticed that after using any ability that has a cooldown they were still showing as usable, i.e the cooldown graphic was not displayed. Additionally, the mouseover tooltip did not show the remaining cooldown either, so for all intents and purposes the ability appeared to be usable even though it wasn't.
First thing I checked was that I had my Show Cooldown settings enabled - yes they were both set to Style 3 and I also had Show Cooldown Text enabled.
Reload UI - doesn't solve
Exit and reopen client - doesn't solve
Delected my character profiles from the 'C:Users**username**AppDataLocalSWTORswtors ettings' folder - doesn't solve
Eventually I discovered that closing and reopening the game client does fix the issue, but sometimes I have to reboot the game several times.
So this morning I logged after installing the new 200mb patch, used Death From Above, and noticed that it was not displaying a cooldown. Without changing any settings I exited the game completely and then logged back in and everything was working again - this indicates to me that it's more likely an issue with the client as opposed to something wrong with my UI settings, but I haven't been able to find anyone else with the same problem yet.. :/
Is anyone else experiencing this?