Zana "Slay Monsters to increase Timelimit" not working anymore

As the title says, just had the Zana (lvl 6) daily "Slay the two rogue exiles within the timelimit, slaying monsters will increase the timelimit" on a lvl 73 mountain ledge map. Slaying monsters did nothing to the timelimit, leading to a fail after the first 38 seconds.