[4.0 HF3] Station drone type change

[Oloka]

My 'MS1' station have 20 drones (max allowed there). Station was damaged so I wanted to repair it by moving some of my cargo drones to repair drones. UI allows to decrease number of drones so I decreased cargo drones from 20 to 12 and increased repair drones from 0 to 8 - see screenshot. The change is not progressing - I still have 20 cargo drones despite I decreased their number and there is no repair drones after a long time. The workaround would be to expand this station so number of drones would be larger or somehow to destroy part of cargo drones but I do not want to do that. Am I missing something here or is it a BUG?

screenshot:
https://imgur.com/BdCj85G
savefile:
https://www.dropbox.com/s/7bqy1vr4f1t0i ... ml.gz?dl=0