Pho3nX im my case, i have played the "sonic" game of the "Mega Drive" system ...when i pressed hotkey + L2, the scanlines works OK on my raspberry Pi 3 ...
the problem occurs only in a specific game system, like super nintendo or other ?
i'm have the system instaled since the 5.5 version and i have updated this from 5.6 and 5.8 ...and the shaders works well aparently on my raspberry Pi 3 ....as i have noticed ....