Most probably we switch back to due missing time to troubleshoot kernel issues like adaptive brightness.
As we know the "old" sources are running very well, just applied 2 more security updates.
Hm, i'm not so concerned about the Display Brightness Issue but the SD Card problems people seem to have in this Thread, i got them too on the Old Build's and after a clean flesh of the lastest Build it's completly gone.
It was such a Headache updating Apps and so cuz it failed 90% of Time.
Maybe we should look in to the cause of this or why the new Kernel Code Path fixed that.
just my 2 cent's keep up you're good Work!