There is speculation and has been for years, the WWE doesn't necessarily play well with others. The most recent evidence that this may be true is the drama that potentially now exists between Chris Jericho and the WWE.
Jericho is the kind of wrestler who spent years working on his craft. He's proven to be one of the top performers in wrestling and as such, has earned the right to call a lot of his shots. He's not under contract with the WWE, and he's free to work with whomever he likes, but he's always seen himself as a WWE guy. That is, until WWE, namely Triple H, possibly changed that.
Jericho has been hard at work organizing a cruise for wrestling fans. He's been spending his own money trying to put on the show, and reports are he waited months to talk to Triple H about including some NXT stars. Triple H gave it some thought but declined. Jericho then turned to Ring of Honor (ROH) and they came aboard.
While the WWE might not be pleased that Jericho turning to ROH, they must have known that it was a possibility. What they likely weren't prepared for is that Jericho may have taken this whole thing personally and as a result, reached out to New Japan Pro Wrestling (NJPW) and offered up his services for Wrestle Kingdom 12. This is clearly a bigger deal than the ROH involvement in the cruise and something WWE did not see coming.
Wrestle Kingdom might not be direct competition for the WWE, but it is one of NJPW's biggest shows and having a "WWE guy" on that show can't be an image WWE is fond of. Speculation is that Triple H has not taken the news well and whether he's upset at himself for turning Jericho away or upset with Jericho for jumping so quickly into something with NJPW, word is the two might be upset with each other.
The good news is that it might just be a Triple H thing (the conversation about the potential riff starts around the 26 min mark). One might be able to compare it to two people who are a bit emotional at the moment acting like they just broke up.
Not everyone feels the same way. Jericho celebrated a birthday and Vince McMahon was one of the first to publicly wish him a happy birthday on social media. This was after news broke of Jericho's involvement with NJPW.
What this means is that McMahon isn't worried. There is a chance that these reports of the WWE (Triple H) and Jericho being upset with each other are overblown, but there feels like there might be tension there. Either way, if Vince is ok with it and understands Jericho can do what he feels is best, maybe both sides now there's still a working relationship in their future.