As someone who has fired more than my share of people, you never wait to fire someone that you know is going to be fired. There is no perfect day to do it - there are always concerns about "who is going to replace them", "how do we get their work done", "what is the severance", etc., you can come up with excuses all day long why it isn't a good time to fire someone. So the correct answer is that you do it as soon as you justifiably know it is never going work out and you sort out the consequences later, whatever they are. Keeping them longer than necessary only breeds more toxicity and simply increases the complexity of the consequences, which is exactly what has happened here. Currie has majestically failed HR 101. He has had 11 months to do and didn't pull the trigger because of this excuse or that excuse when anyone with a brain knew it wasn't working out, and now we are likely stuck with this shitshow for yet another year. Complete failure on his part.
Absolute worst-case scenario was that he fires Manning, doesn't pay the buyout, and let the lawyers sort it out in a year or two and settle for some amount on the dollar. That happens EVERY DAMN DAY, yet he has been too much of a pussy to take a stand, and now we are stuck here.