You didn't say how long ago this happened.
If nothing else (heat or cooling system) happened for a long time since it did, it's probably fine.
But the flush and coolant change questions are good ones.
I've only rarely had the fan come on for the length of a red light. HOT days, stop and go. Where I live, some red lights are very long.
If I get stuck in traffic, I always reach down and key the bike off (before the fan comes on). Do not shut down with the the kill switch or kickstand switch and sit there with your lights on.
It happened to me several times the other day, and also put the kickstand down and just sat there waiting to move (85 degrees). I always worry like an old lady the bike won't start again (HOT), but it always fires instantly.
I have these Tel Tru sweep thermometer oil dipsticks in both Interstates (kind of spendy). 220* is where you want to start worrying. So on hot days at lights or backups, you can look down and see how you're doing. They have an oil level line, but I don't trust them and only use my OE dipsticks for checking. And it's been a long time since I checked them for accuracy (you stick them in boiling water and adjust them to 212* - sea level). And you mustn't unscrew them with the dial face or you'll change the temp setting; you remove and snug them with a wrench on the hex neck.
https://www.teltru.com/product-category/home/motorcycle-and-atv/?srsltid=AfmBOoodcGJnr-1ud683rUenty8dkeaE-WzIz_rAfbCJQbM2KmeUQ9jc