Truth be told, this sounds like the bug, not your situation. If you queue for the group finder and choose specific FPs only out of a tier, then the interface will tell you that you aren't eligible for the daily BH comm reward. You MUST choose random. I went in with a completely preformed group and got my comms as soon as the instance was finished, but we chose any T1 HM flashpoint.
I agree it should be a bug but why a guy choosing an specifc instance ( for example Taral V hard mode only) joining alone and getting a pug group is getting the daily reward and a full group not?. I dont understand, is just silly. Group finder rewards pug and not full groups of friends?. We must be 3 friends + 1 pug to get the daily reward?. Is non sense at all.