I only noticed this on Awakening Tamer, so I don't know if it is an issue on any other class. When the black fox appears and maxes out the Black Spirit Rage, I can use Legendary Beast Dance to perform the 200% BSR skill. BUT... if I don't use it immediately and try to keep it for when the boss appears.. I can't use it. My character uses the normal version of the attack then, even though the bar still shows 200%. The same happens if I lock the BSR skills and unlock them: I can't use the 200% one anymore. I can still use the 100% one twice in a row.

Are you certain this is due to the 200% not working? There is 30minutes cooldown between using a 200% attack skill, and during that time you cannot use any 200%. Perhaps the times you tried to use the skill fell into that timeframe? Just to make sure, because i know the 30minutes cooldown isnt known to everyone.

Oh, it's probably that then. I forgot it had such a long cooldown. In that case, this is solved, thank you.

The cooldown has changed to 20 minutes since the BSR rework.