did you tried to switch the bios from silent to OC ?
What bios you modded ? silent or OC ?
did you saved your cards original bios file for each cards ? , card 1 -  bios 1 , card 2 - bios 2 ...
When you flashed back the bios are u sure u used the right bios for each cards ? card 1 -  bios 1 , card 2 - bios 2 ...
those cards can have a different bios version , just like the RX 480's