Throughout the past couple years, especially since the last round of combat changes, we have been making adjustments to companion powers to address the drastic imbalances across them. Work is done directly on the powers which, unfortunately, can result in specific companions being impacted and that specific information not reflected in the patch notes. This is also exacerbated by the ongoing nature of the work being done. We understand this is frustrating to many players and how this can come across as an intentional lack of transparency with updates.
The most recent example is the Air Archon companion, where Flail Strike was dealing single target damage as an AoE. This power's issues were found during other work and fixed, which resulted in the specific fix documentation failing to get into the patch notes. We will try to be better about this going forward.
Balance work will continue in the future as part of regular development. Adjustments are made based on direct feedback regarding other over-powered companions as well as imbalances we find as a result of other investigations. There are plans to make adjustments to the following companions in a future patch: Xuna, Abyssal Chicken, Black Ice Prospector, and Cold Iron Warrior.