I can confirm bug with wrong hashrate if you use "-li" or "-ttli" options. These options add delays after every GPU round, so GPU is free for some time and therefore it becomes cool. But v12 measures GPU round time not including these delays so you see same hashrate. I will fix it in next update. This bug was added during porting miner to Linux, I don't remember exact version number.
Another bug is - broken -di command on (mixed?) system with 3 x RX-470 + 2 x R9-280X
ie: if i put -di 2,3 it starts 3 cards instead of 2 ...
everything workis fine, if i put -di 0,1,2,3 etc.
**** EDIT:
All works fine if i put -di 234 ...
Didnt pay attention, since i just copy/pasted bat from older version,
and it worked on previous version(s) ... strange
so, is it bug or not ... now i'm not even sure
b.r.
Alex