Flickering not present on real hardware

[GValiente]

Test ROM

In the scanline marked by the red arrow, there's some flickering not present on real hardware. Map scale is updated each scanline in a H-Blank interrupt, so the flickering is probably related to that:

[Margen67]

Duplicate of #287

[fleroviux]

Closing as this is an exact duplicate. Weird, probably Github glitched out or the form was submitted twice.