I had the same "naughty" experience with my last Flame. It seemed to do the same. Swim up to another fish just to be a nuisance. Swim around, swim under, etc. All to get some reaction then swim away to bother the next fish. Nothing ever aggressive. Made it actually one of my favorite fish for this behavior. Never picked at coral. Great fish.
Hope my new one (in QT now) will be as cool. It doesn't seem to bother anyone in QT, but it does swim non stop like it's mad all over the tank. A bit concerning to be honest, but it really is non stop like it's crazy. Not eating enough to have that much calories and energy. Not messing with anyone else which is fine, but I'm just hoping it won't mess with coral in DT otherwise it'll go.