There seems to be some confusion in the succession of ranks.
 

Oddities, since some missions, I am promoted Kapitänleutnant at the end of the mission, I decorate the crew and I leave for a new mission.
And there rebelote (in French means again), at the end of the mission I am again promoted to the same rank!
Looking in the menu file I see:
160 = MatrosenGefreiter
161 = MatrosenObergefreiter
162 = MatrosenHauptgefreiter
163 = Bootsmann
164 = Stabsbootsmann
165 = Stabsoberbootsmann
166 = Oberfähnrich z. S.
167 = Leutnant z. S.
168 = Oberleutnant z. S.
169 = Leutnant z. S.
170 = Oberleutnant z. S.
171 = Kapitänleutnant
172 = Korvettenkapitän
173 = Fregattenkapitän
174 = Kapitän z. S.

There seems to be some confusion in the succession of ranks.(166 at 170)

Has someone already remedied this problem?
Why a demotion after 171 = Kapitänleutnant ?

Should be modded out indeed but might be hardcoded. I also saw it happen.