This is common at armor dealers, since they only have 4 (Edit: 5?) ports. Often, only one is free and it's reserved for the player or Korolov freighters they're escorting. This causes AI traffic to get stuck trying to dock with the station, which is silly and can prevent Korolov missions from being available.
Commonwealth trading posts in Eternity Port often fill all their docking ports, not leaving one for the player. I've seen this happen (very rarely) at other stations, too.
Some or all of these suggestions might help:
- Give armor dealers more docking ports.
- Reduce the amount of time wandering AI ships spend docked at stations.
- Make guards that are permanently assigned to a station patrol it rather than staying docked, either all the time or when the number of free docking ports gets too low.