This event is unreliable.

• Can fire twice or more times when the player clicks to "activate" a different specialization.
• Can fire when entering an instance via the group finder even if the player's selected role already aligns with their current specialization and thus no change actually happens.
• Can fail to fire in the above group finder situation when there actually is change.

As a result, I'm better off ignoring this event and tracking the player's specialization manually keeping hope that Blizzard's API provides more accurate information which as we all know is never guaranteed.

2 part solution:

• use ACTIVE_TALENT_GROUP_CHANGED event instead
• it also fires multiple times, so, I must manually check if the spec is different from the last time it fired and ignore the duplicate events.

fixed as part of massive May/June 2025 rewrite