Hey y'all. I just had my carbs cleaned a month ago by a mechanic, and I've noticed my RPM's have been a little weird. When i first start the bike up cold, the RPM's go from 0 to 2000 and then drop down to about 1200, which is normal. After the engine's warmed up, idle speed is about 1500. When I do a decent amount of riding (a couple miles at minimum) the bike's idle speed is around 2000, but if i stop moving it drops down to 1500 after a few seconds.

How quickly should I get this fixed? I'm not sure what the problem is, but I'm not very good with self-repairs, so if I have to take this into the mechanic, how urgent is it of an issue? The bike still runs just fine.
What should i do?