In the past they would instance the zones they expect to have the highest traffic when the new MSQ content was released to reduce the load. Considering the congestion and the amount of lag I had in The Lochs and Azys Lla, I wish they had done it again. My system usually handles congested zones (from large hunt trains) fairly well but I was feeling it today.

Maybe they're using the patch as a stress test to see how much load the zone servers can handle as they prepare for next expansion? They've been using 3 instances but if Endwalker has another burst in player population like Shadowbringers did, they may decide to increase that number.