When move playhead it starts jumping back and forth, then stops

Clock set to internal.
Basically, cannot put playhead into precise position, it keeps jumping back a little after I release it. Sometimes jumps back and forth after I release it.
Ardour 2.7.1

make sure you don’t have grid or magnetic enabled, or set the grid to be more precise for you.

I tried all that, it was not helping. eventually, after restarting ardour several times, the bug went away. But I am curious what it was.

you should update ardour. the new version is 2.8.10…there are a lot of buxfixes and improvements!