I have always felt that there was some wonkiness to the 12* unit drop rates. In the past, when there was a week with no RDR boost, 12* unit drops were pretty rare. Then, during an RDR boost week, my 12* units drops increased GREATLY (here I am thinking of Ray units in Amduscia UQ).

On a somewhat related note, this week in the Revelry LQ with the 158% boost, I have been given one 12* DF unit drop on almost every run.

For the record, I have only received one Celestial unit (one rear), but I have to preface that by saying I don't have my 50 run title yet (I haven't been able to play as much as I used to due to family issues).