Sorry for my English, not native speaker.
I suppose, Russian-language tech. support isn’t working, that’s why in-game support are not answering me. So here we go.
When i, as protection paladin, places my consencration pool on other, already existed pools, my Mastery does not appear. Tested on several paladins: random protection paladin without party with him/her; holy paladin 70-th lvl in Dornogal, 80-th holy paladin in Dornogal, 70-th holy paladin in Dorn and inside instance and 70-th paladin in Valdrakken without The War Within. In last case everything is work as intended, no issues with mastery.
I captured some videos of that bug:
(https://youtu.be/5O-rCFMKZ6A?si=FvqP8C2W-SqV90b7)