That's not right. It's a "bug" kind of thing.
Basically, it's a loading issue. Sprays are like the last thing to be loaded into the engine, so when you watch anything under highlights it's not very common you get to see any actual sprays.
I've seen/done this enough times to be able to tell. I've even spotted it a few times where I lay down the spray, it shows the generic one, then 2 seconds later it "updates" to show my actual spray.
Well i figured it made sense, because i've definitely seen sprays show up when pros do it in competitive. And i think i've only seen them put down the tea time and the speech bubbles, so it kinda made sense. That or it's just that it loads faster on PC.
Oh well.