That contradict ~30 years of Forgotten Realms lore. I would be rather surprised that WoTC would just allow the devs to change that. Even more curious, the place where we find him was a Selûne's chapel just a few months ago (in demonstration) and everything related to that is still in the game files.
I honestly don't know how accurate these descriptions are. Just that he is called Jergal in them and all his files say 'Jergal' also. As for the tomb itself, there a dialog with Shadowheart: PC: The air's stale. It's been centuries since any prayers disturbed it. SH: Who were those prayers for? Normally the patron god is obvious - not here. And there is Jergals statue, so at least this particular room hasn't been dedicated to Selune lately.
I'm not saying they are inaccurate, I'm saying it's break the lore into pieces and that the place where we find him had a different story and they didn't bother scrubbing the game files of it.
You could clearly see the Selûne's symbol on banners back at E3, they changed them to banners that don't even have Jergal's symbol on them. The statues were probably changed too. They nixed some of Shadowheart's special dialogues that referenced Selûne but the game files that trigger them still exist.
It's just a strange change for the sake of making change. On top of that, his service breaks the game, as he should be able to cure you of the tadpole...
