Now this might be intended, so maybe not a bug as much of a drawback. I've been doing some testing, using the multiple accounts to enter runs as omni, then have one toon leave and re-inv someone to see if they get credit towards the omni run. I know we've all been invited to an omni run where after it finishes and we don't get credit, arguably...we shouldn't either. It seems to partially be tied to the cross faction part. Tested using 8 toons. All hero. Entered a run, had 1 person leave, get invited back, finished, they get credit. Re queued, had one leave, Invited a new toon who didn't originally queue as omni, but is also a hero and they get credit. I've done this all the way down to where there is only 1 person left in the original omni group, and invited 7 alternate hero toons, and they all get credit. The only exception for the same faction is if the toon who queued the original custom run does the invite, that invited toon won't get credit, which makes sense. However, if you invited a villain, they do not get credit. Or if the run was queued custom by a villain and heroes join, then someone leaves and a hero is invited, they don't get credit. So inviting to the run does not seem to be the issue...the cross faction does. Again, maybe this is working as designed, just funny that an invite of the same faction by an omni queued person is fine....but of an opposite faction person is not.
Omnibus runs are not exclusively omnibus groups. Omnibus is, in effect, queuing for 99% of instances, whether they be raid, alerts, duos, or solos. It is entirely possible for a raid to be 5 people that queued specifically for that raid, and 3 people that queued for omnibus and were thrown into this raid because if needed to fill spots. Your issue statement is also your answer. You are not queuing for omnibus if you are invited to an instance, and therefore receive no omnibus credit. Until I've seen any developer input, I'm inclined to believe that an omnibus-queued individual that explicitly invites another character to the raid, bestowing omnibus credit on the invited character, is likely the bug.
And as I said, that might be it. However, I did test where it was pure omni (8 man group queued omni) and where it was 7 omnis+ 1 custom. Both give credit if an omni person leaves and new person is invited. However only once cross faction is thrown in, the issue arises. I guess it was more of an explanation of an issue some have reported in the past vs a new bug. Not getting credit for SOME runs when invited to in progress runs that the inviter queued into omni. I'd guess most were opposite faction runs after doing some research. Maybe no one should be getting paid if invited, but that's not how it's currently working for better or worse.
