It's quite normal.
Tiger used to do that to everyone. Finau did an interview about the 2019 Masters and he said Tiger didn't say a word to him all day. Tiger used to start walking to his next shot the millisecond after his playing partner hit their shot so the guy saw Tiger 20 yards in front of him when looking to see where his ball landed. I want my athletes to be like this - not pussies like Bryson who get butthurt when someone won't talk to them.
I'm sure if Rory was paired with Rose they would have talked, they're boys. Rory and Bryson don't like each other and they're competing, why the hell would they be buddies on Sunday?