This applies to PVP. I do not use unbreakable for PVE, so I wouldn't know whether this also occurs on that game mode.
Anyways, for some time now (maybe during the last year or so), it is very well known that if you have any piece on your gear with arm regeneration, your unbreakable talent may bug, and it would not trigger.
Could you please comment down below and raise awareness on this matter? I do not believe I have seen many people speaking about this, but it is definitely game breaking at least for PVP (and yes, I know a bunch other stuff are broken or incredibly unbalanced for PVP as well)
Thanks!