The effects of Carow Golan are suppressed if a character using it wears the Talisman of the Unconquerable. Sometimes, the suppression doesn't occur until a character in the party does any kind of action (Such as moving or activating a modal ability). Is it a bug or working as intended?

 

The Carow Golan doesn't suppress or get suppressed by the Brîshalgwin Mindmarker.

It's a problem with all the items that give bonuses that are tied to a special "if". Blood Tempered Helmet, Drinking Horn of Moderation, Mantle of the Dying Boar and so on. They all suppress or get suppressed.