Character progression is a core element of World of Warcraft, and that includes PvP. In Legion, empowering your Artifact to become stronger is a key part of character progression. When Artifact Knowledge levels were low at the beginning of the expansion, we deactivated the 35+ Artifact Traits in instanced PvP to avoid having large power gaps when compared to players who hadn't made much progress on their Artifact yet.
In Patch 7.1.5, we added several methods that allow players to catch up their Artifact progression very quickly. Brand new players can advance up to Artifact Knowledge level 15 without any research time, and existing players can mail Artifact Knowledge Compendiums to alts, which immediately bring them as high as level 20. At this point, the power gap between a player with 35+ traits in their Artifact and a player just starting out is significantly less of a concern, as the gap can be closed very rapidly. For those reasons, we felt that Patch 7.1.5 was the right time to re-open Artifact progression to PvPers who had already earned the first 34 traits.
However, we did not communicate this change (and its purpose) with enough advance notice to allow players to effectively prepare for it. Furthermore, while the improvements in Patch 7.1.5 make it much easier to unlock those final traits for new players or alternate characters, they weren't available until today. While we still believe activating these traits is the correct choice for World of Warcraft PvP, the middle of an ongoing season is not the right time to make this change.
As of a few minutes ago, we've applied a hotfix that once again disables the 35+ Artifact Traits in instanced PvP on North American and Oceanic servers. In other regions, this hotfix will be applied with the patch. The 35+ Artifact Traits will remain disabled for Legion PvP Season 2.
Once Season 3 begins, we'll re-enable them. Note that Patch 7.2 will include some further expansions to the Artifact system that will make it highly valuable to have spent some Artifact Power on those traits (another reason we feel it's important that they be enabled in PvP). We'll have more details to share on those changes once Patch 7.2 has begun its public testing phase.
Thanks for your feedback and understanding on this topic.
This is a bug and we currently have a hotfix in the works to resolve it. I'll update this thread if I hear anything more.
Thanks for the heads up, and we appreciate your patience on this.