Brandi Glanville and Lisa Vanderpump’s friendship on “The Real Housewives of Beverly Hills” has been so famously strong that it’s at times left other co-stars alienated, but according to reports, the friends are currently on the outs.

According to E! News, the trouble started while the castmates were shooting footage for the upcoming season of the Bravo reality show on location. An insider who spoke to the publication hinted that something “went down while they were all in Puerto Rico,” but declined to give specifics. However, Glanville addressed the alleged feud on her own Twitter account, acknowledging on Wednesday that the pair had hit a rough patch.

Glanville, 40, responded to a tweet from a follower who wrote, “I can’t believe @BrandiGlanville & @LisaVanderpump are no longer friends ): crying already [sic].” Glanville in turn shot back, “We are not, not friend [sic] I love her we are having a bump in our road.”

When another fan followed up on the gossip asking for further clarification, Glanville added, “I will always love her but sometimes friends have hic-ups [sic].”

Although Glanville has a reputation for igniting drama, both on reality television and on Twitter, where she regularly spars with LeAnn Rimes, stepmother to her two sons Jake and Mason, the gossip publication hinted that the fight might have been more Vanderpump’s doing. A source told the site that Vanderpump was “not getting along” with any of the “Real Housewives” cast members after the vacation.

Although Glanville and Vanderpump have both stayed tight-lipped on the source of their alleged spat, RadarOnline reported that Yolanda Foster had driven a wedge through their relationship. According to the website, Foster confronted Vanderump during the trip, and accused the restaurateur of being a back-stabbing friend, a charge that Glanville allegedly didn’t discourage.

Further adding fuel to the fire, Radar Online reported that Glanville has recently been spending time with Kyle Richards, another former friend of Vanderpump’s who had a falling out with the reality star.

An insider told the site that Glanville and Richards “have become a lot closer after the Puerto Rico incident…The two have been spending time together.”

“Brandi felt bad for her role in going after Kyle about her husband allegedly cheating on her. She had gone through hell when her hubby, Eddie [Cibrian] hooked up with LeAnn [Rimes] while they were still married. Kyle has been very receptive to Brandi,” the source added.