Underoath was scheduled to spend the summer of 2006 on the main stage of the Warped Tour, but on July 28, 2006, it was announced that Underoath was dropping off the remaining dates of the tour. A statement from the band stated that the members "felt it necessary to take some immediate time to focus on our friendship, as that’s more important than risking it for the sake of touring at this time."
Rumors to the contrary, however, flew that the band had actually left because NOFX frontman Michael "Fat Mike" Burkett had made fun of Underoath and their religious beliefs on-stage. These rumors were debunked when Burkett told PunkNews.org in a statement of his own that Underoath's claim of needing a break was indeed true. Burkett did admit to poking fun at the band and criticizing their stance on gay marriage, but emphasised that he befriended Underoath's band members at the start of the tour, had very civilized conversations with various members right up to the band's departure, that he had a personal policy of not making jokes on-stage about anyone he wasn't friends with or didn't like personally, and that there were never any hard feelings between himself and Underoath's band members.
In an Alternative Press cover story on Underoath, Burkett told the magazine that Spencer Chamberlain had confided in him that Underoath's band members had been "having a lot of arguments over their religious beliefs.". In a sidebar of the same article, Burkett stated that he was "not calling Underoath homophobic, but they're against homosexual people having the same rights that straight people do. I find that to be bigoted."
In a January 2007 interview with Ultimate-guitar.net, Tim McTague stated the following when asked about Fat Mike's involvement in Underoath's departure,
"That wasn’t an issue. I mean, that was an issue on the tour in the sense of like there were some things that were said that probably shouldn’t have been said by him. But it never really got to the point where it affected us. That wasn’t the breaking point really for us at all. I think he definitely played a role in making a lot of our stuff public and exaggerating a lot of our beliefs and a lot of our conversations that we had to him. So he definitely loves to stir the pot, and I’ll give him that. But beyond that, we shouldn’t have been on Warped Tour to begin with. It definitely wasn’t a Fat Mike thing."
Looks like it probably had something to do with them leaving. Anyways, I saw these last year at the Taste of Chaos and they were really really good.