[Toni Wilen]

Originally Posted by amilo3438

Pax Americana by Complex -> http://janeway.exotica.org.uk/release.php?id=19676

QS A500 OCS/ECS (see pic.1)
QS A1200 AGA (see pic.2)

Does it happen also on a real A500? (didnt find anywhere mentioned that is AGA only)

It (accidentally as usual) writes to blitter registers while blitter is active. Results can be quite mysterious (blitter can stop, it can suddenly do something impossible and more..), practically impossible to fix without having blitter's original logic diagrams/schematics.