Robert Pirès lived an difficult moment after the CL final. It's impossible to understand the delusion and the angry which he felt for Arsène, despite he was a father figure. Probably is better when there is a "sentimental distance" with other manager, with the respect of the roles, because when you are too mental and heart connected with your boss, his choices tend to ruin the relationship.
Now I'm happy to see them with the smile on them faces. Robert probably tried and has removed the bad memories and Arsène tried and has accepted his " toxic - and probably right - emotions" after that day.