I've seen a few people report that lately, but I'm not sure that it's been acknowledged as a problem. Could you have anything preventing the communication between the two? (vLANs, firewalls, etc.--putting Hubitat on the same router/switch as the other if you're not sure would be a good idea, but then it's still odd both that communication works in the other direction and that you can get some data from the Bridge, since the list of lights and groups comes via a similar mechanism.)
I did write a custom Hue Bridge Integration ([RELEASE] CoCoHue: Hue Bridge Integration (including scenes!)) but don't want to steer you towards that as a solution to a problem you shouldn't be having. 
That being said, if you're in a hurry to get things working, that is something I'd actually be able to troubleshoot. Otherwise, I might suggest dropping Support an official line to let you know of your problems with the built-in integration to see if they have any ideas.
