Still seeing this in a new game on a fresh install. Not all abilities seem to be affected, though. Frenzy is and savage defiance isn't, for example. Also, it only permanently extends the duration of abilities belonging to the character using spelltongue, not buffs received from other sources. Respeccing the character (or removing and re-adding the ability in question via console) restores the original duration.
Oh well, at this point I'm getting used to the idea that being teased with cool stuff that's bugged beyond usability is a core aspect of the PoE experience.