Grey/pixelated screen on some rides when pushing over 1.6x

The grey screen issue I have seen with v7 seems to happen on certain rides, e.g. This mornings Adelaide City to Glenelg (crazy cats group ride or the version in ‘trending’) Anything over 1.6x and the screen goes grey and pixelated, under that is fine.
Seems to happen when stopping at lights, around corners, when original rider slowed down.