Loosing the warhorn buff on map change

[Civilix]

After the last patch i have noticed that i sometimes loose the warhorn effect when playing, i am not sure if there is something spesific that triggers it as i have yet not been able to reliable reproduce the bug. But i do notice it when 'a darker shadow' quest does not update on the second or third area of the instance. Anyone else experienced this and maybe know a workaround to not have it happen.

[Fass]

It happens when you change specc as the buff is not blacklisted.

[cynara]

I lost the buff while porting from Conall's Valley Night into the Blue Mountains. I only noticed it after killing the boss in the Blue Mountains and not getting a quest update from the hardmode quest... I then ported to Conarch Village, waited for the Blue Mountains instance to reset (it only lasts 30 min), used the horn and talked to the runner NPC who then ported me back into the Blue Mountains (which was the hardmode version now with the boss respawned as well). After that, the horn buff stayed on me for the remaining 2 instances as well. (BTW I'm pretty sure I wasn't switching my spec at any point during all this, so there must be something else causing the buff to be lost as well.)