I now have 8 officers?

I helped retake the enigma machine on board a sunken U-boat. One of the 2 sailors I rescued who were banging on the hull as my diver came by, have now joined my crew.

This brings my total officer count to 8.

3 Leaders, 2 Engineers and now 3 radio officers?

I just completed the mission and started a new one and Prien is still among my crew. I guess it's possible to have more than 7 officers on board lol. Have anyone experienced this?

Edit: Boat wouldn't let me leave the port unless I told Dr. Prien to Disembark sadly.