Rolling a spray paint cap on a surface

[TheWonderer1]

Hi there,

I noticed that when I release the cap it moves forward slightly (away from me) which I attribute to the surface being not level and my hand applying a small force. However, the cap will roll backwards afterwards (towards me).

What is causing the cap to roll back and forth? It appears to stop and then go in the opposite direction. I thought it could be friction but I always thought of the object as coming to rest rather than changing directions.

 

[TheWonderer1]

It's possible the surface is dented. Also, there are grooves which might cause changes in weight on each side.