If we're talking confirmed actors it can only really be
>RDJ
>Pedro Pascal
>Ryan Reynolds
>Hugh Jackman
They're the biggest money makers they would cater to. The question is who vs who. Doubt it was RDJ, I think he's paid enough not to let things get under his skin, and it's impossible to shoot around him given the nature of his role. It can't be someone like Antony Mackie or Patrick Stewart, because the former isn't that big of a pull to boss around and the latter is too old for this shit to start drama. So that leaves Pedro, Ryan, and Hugh. Hugh and Ryan are good friends, so it's a matter of determining what Pedro said to one of those two, or vice versa.

So deduction tells me, and please correct or debate me otherwise, that Ryan made an offhand crack about or to Pedro which resulted in him throwing a fucking fit since he's all sensitive and shit in interviews. Pedro is supposed to be the new "Tony Stark" flagship hero in this new phase of the MCU, so it would make sense that he would be catered to. That and it's easy to write around Deadpool. ADR, post production placement in shots, even using a masked double next to Pedro