It's hit and miss for me too.
What I do to get it to work (sometimes), make sure I am out of combat mode and I make sure Tank is not running. Click on the UST button, then I hit the Pause key to turn tank on.
Sometimes that works, sometimes it don't.
DtB
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The more people I meet, the more I like my cat
Retired-Lvl 251 Battle Dagger/Sword Bear, Bunny Master

Retired-David the UA Bear-Lvl 250-Queen Slayer

Retired- Lvl 275-David the Mage Bear-David's Rare Bear Lvl 275/Died 887
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