I have seen a lot of times and 1 time happened to me, but it was in a early stage of a tournament and did not improve my stack a lot, but was not bad. Most of the times royal flush is happening when there is going to be a brutal bad beat for the specific person and the software has decided that this is the time that person to be crushed. I have been noticed this a lot of times.
In live poker I have seen many, many royal flushes and straight flushes. But with that said, it made me think that online poker you have a lot more flushes, quads and full houses than live poker. While playing online poker I have only seen one royal and that was on BOL and the royal was on the board -- the two players in the hand split the pot . . .
I've had a couple in the past few months, seen perhaps a half dozen more in that time. All of these were online, on pokerstars.
I got one of them in a CC tournament, got paid at showdown, and received not one single comment or even so much as a "nh".
Live, I have not had one but have seen many. Most recently was in 2019, before the pandemic, when life was carefree (except it wasn't).
Once you start playing a lot of online poker, they just come up more frequently, and everyone likes to show it, even if everyone has folded...so that is one hand you just get to see. It's like quad aces. Few people can resist showing that beauty off.
The hand has a probability of 0.000154% or 649,739:1.
I guess I'm lucky as I've only played about 120K hands over the past quarter or so. Far fewer than would be typical to see just one.