Thank you for reporting - @BGK and @mosen!

Re speed jumps in the cities: speed is not related to the smooth movement, its displayed without any interpolation on PM side.

Re jumps: Smooth movement has effect only on drawing position (but not on instructions, these use proper position) and center of the map. I have been using it on slower speeds without any issues. I think its more related to the goodness of GPS signal and I should account for that.

Re glitch in follow me: PM is not using compass. If you use follow me with OSM Scout Server's map matching, it could be explained by a particular glitch in estimation of your movement on the basis of your positions (it tracks a short history). Instead of reboot, start and stop should have worked. Alternative explanation would be that you were driving on one-side street in opposite direction. For example, going for Pro1 event in UK and forgetting that they drive on somewhat different side over there.