Frigate stuck in Europe

I sent a Frigate to Europe and now I can't get it to return to the New World. Clicking on 'sail to east' or 'sail to west' doesn't do anything and neither does dragging the ship to the outbound lane. I haven't seen this happen before, not that I normally send a frigate to Europe, and my trading ships are unaffected. Saving and reloading the game doesn't help either. Has anyone else had this problem and is there a solution?

(Vanilla Col with the patch)

Edit: That Frigate stayed in Europe for the whole game. Other ships, including another Frigate, continued to arrive and leave normally throughout the game without any other problems. Strange.

It happened again, this time with two galleons. Neither of them would leave Europe either sailing west or east. However in this game I was able to isolate just when it occurred. I was playing as Spain and preparing to fight the Dutch so my galleons were docked in Europe. They became stuck there at the moment I declared war. Before that point I could move them out as normal.

Luckily I was able to go back to a save game to make sure my galleons weren't in Europe when I declared war.

I already had this pb, but only when I played with the vanilla, I think the system of seaways solved this pb.