I'm noticing an odd bug with cooldowns on butterfly wings, not sure what triggers it but the only consistent thing I can see has been going through warps to different maps.
To give you some examples, I'll use a bwing to get to Izlude, then start flying towards Prontera. Once in town and business is concluded, it shows no cooldown for bwing. Once I attempt to use it, it doesn't work and there's no message saying "can't use it yet". If I do a character relog, when I get back on the character the cooldown shows back up for however much longer there is.
This has happened other times when going back to take care of older bosses like Robberbug/Lurker Fly and such as well, hence why I say the only consistency is going through warps to different maps.