After update, all crews except "Alpha"are locked. Two of my ships was used crew “Bravo” before, so I tried to switch to crew “Alpha”, then the game said “crew assignment/switch error: general error.” Then I purchased crew “Charlie” and switch it but the game still said “crew assignment/switch error: general error.”
I have exactly the same problem. I had second crew bought. And third crew by rank 15 with feds.
After you changed system i got reimbursed and 2nd crew was removed. Now I cannot switch crews from slots nor cannot use any crews in the 3rd and 4th ship slot.