thats ok - I'll answer in the same (and apologies to others)
1) I think its slow, its best if you have a lot of spare replacement chits
2) I fear is a bug, it has occured in the game before so it may have come back
The solution is not easy. You either need to write an event to eliminate the current unit and replace it with one with the proper elements or know how to change the save file.
PM me if you want help with this - use French or English as you prefer.