Chris Brown and Rihanna: On the Rocks After Grammy Love-Fest?

At the Grammy Awards Sunday, they couldn't have looked happier by each other's side, but are Rihanna and Chris Brown already at odds again?
According to the Mail Online (UK), the couple refused to even acknowledge one another at the Playhouse Nightclub in L.A. on Wednesday night.

Rihanna Blows ... A KissBrown in Black and White
The music superstars arrived separately at the Popular Demand 1-Year Anniversary event, did not speak, and left alone at the end of the evening.
Chris Brown arrived at the celebrity hotspot around midnight with a crew of about 20 people. Rihanna entered half an hour later with her bodyguards.
The singers never once communicated with each other during the course of the evening as they sat across the room from one another, said the source.
Says one fellow club-goer:
"He promptly ordered three more bottles of Ace of Spades which came out with in a procession of sparklers and scantily clad cocktail waitresses."
"That caused a huge spectacle, which he clearly wanted Rihanna to see."
Clearly. Chris left the club around 2:15 a.m., 45 minutes before she did. They were probably just doing their own thing on this night, but it makes you wonder.
The chilly atmosphere between the controversial pair is a far cry from their loved-up appearance as they sat side by side in the front row at the Grammys.
Not everyone was a fan.
Rihanna's former best friend Katy Perry does not approve of the reconciliation with Brown, who is still on probation for his felony assault on her in 2009.