Glitches. They can happen at any time, anywhere on the map. Some are predictable, some only happen under extreme circumstances. I found one of the latter.

3244246
lol, it happened to me too just today, in my sherman on one of the artic maps.
if it happens once, it's a YouTube video.
if it happens twice, its a coincidence.
three times however, that's a trend...

Hey, group! Anyone else have their tanks do sweet donuts while on a slope!?