Definitely a bug. I encountered a similar problem today and yesterday when trying to dock two satellites together.
Viewing from satellite 1, I get a expected relative speed (<3m/s) when setting satellite 2 as target, but when viewing from satellite 2 when setting satellite 1 as target, I get several hundred meters per second, which is obviously wrong. Reloading the saves cannot solve the issue, while restarting the game can. I don't have any screenshots left unfortunately.