I have already bug reported this issue ingame, made a post in the HoT bugs thread (page 44) and posted in the warrior section of the forums (5 months ago, apparently) but this is still happening.
When a berserker enters berserk mode a 15s “time remaining” countdown is meant to appear on the berserk icon to let you know how much time you have until berserk expires. After berserk has expired a 15s cooldown is then displayed on the icon to show you how long until the skill is ready again.
In PvE the “time remaining” countdown is correctly displayed, however if you take the trait Smash Brawler (which reduced berserk’s cooldown time from 15s to 10s) then the “time remaining” countdown is also reduced to 10s, which means it ends when you still have 5s of berserk mode left and you have to rely on the buffbar icon’s flashing to know how much more time you have.
When I last checked, the “time remaining” countdown is also accelerated and slowed by alacrity and chill respectively, which will also cause it to become inaccurate.
When in PvP (I haven’t checked WvW) the berserk icon fails to show any “time remaining” countdown at all, and goes blank for the entire duration of your berserk mode.
Below is a screen shot showing (from top to bottom) the completely blank icon you get when in PvP, the timer that ends 5s too soon if you use Smash Brawler and then the relatively functional timer you get if you do not use Smash Brawler.
