gamedev.stackexchange.com/questions/98851/body-lost-a-velocity-component-when-hitting-a-wall
Basically there may or may not be box2d properties we are not able to access to fix this.
But the gist of it is that this likely happens when you have very very small values, which probably are occurring because you have very very small sprites. Based on solution 3 suggested by NauticalMile on that page, it sounds like there are two things you can do to try to improve the situation. You can either size up your assets by a lot (and scale them back down again later) to trick the box2d library into thinking its working with higher speeds (more pixels/second), or you can simply increase the speed and forces you are applying on everything, and then lower the timescale.
I would try scaling everything up by size first, as the second option would affect the actual distance your ball travels without tweaking, since you do expect your ball to eventually come to a stop, unlike in a breakout clone.