Paul it really difficult to gauge this as a problem, mine will snatch but this only happens on rough roads with pot holes towards the edge of the road surface.
I have experienced similar before in older cars and have assumed that its part of the outcome of using narrow tyres. I think the only way we would resolve if this a single or multiple vehicle issue would be some back to back tested.
Certainly where I've experienced this it has been on roads where the surface wouldn't be suitable for a motorbike unless of the off road type.
