no it isnt untill the fight is over.. its over after 2 hours.. if you still have to wait half an hour for your generals/support units to arrive. then quarter of the buff is already depleted.. you still need to fight allot depending on the dificulty..then before you finish the adventure you already have debuffed.. and then for next buff you have to wait a whole 24 hours
your wrong the buff might only last two hrs for you to activate a adventure in but as long as you activate the buff wait for it to appear in the buff section at the top of the screen then start your adventure you will get the bonus xp no matter when you finish the adveture if your good enough to finish within two hrs you can stat another even if you only have a few minutes left on the timer you will still get the bonus for the whole adventure even if it took you a week to do it
425k on Giant Battle with premium (+35%). Nice result.
https://prnt.sc/l8kh84 from the final battle using the outpost 1.2 mill plus prem and wasnt a complete clear would love a map for the whole adv