If you fire your founder CEO you need to be on top of messaging. Your major customers can't be surprised. There should've been an immediate all hands at the company. The interim or new CEO should be prepared. The company's communications team should put out statements that make it clear why this was happening.
Obviously they can be limited in what they can publicly say depending on the cause but you need a good narrative regardless. Even something like "The board and Sam had fundamental disagreement on the future direction of the company." followed by what the new strategy is, probably from the new CEO.
The interim CEO was the CEO and is going back to that role. There's a third (interim) CEO in 3 days. There were rumors the board was in talks to re-hire Sam, which is disastrous PR because it makes them look absolutely incompetent, true or not.
This is just such a massive communiccations and execution failure. That's why they should be fired.