dnd 5e – Warforged Cleric of the Forge starting with too much HP… why?

Created a Warforged Cleric of the Forge, Using the official D&D Beyond tool. It came out with 15hp at level 1. Where did the extra 4hp came from? I have a 17 CON for a +3 bonus, so it should be 8+3=11, yeah?
I also re-made him using the Fight Club iOS app, and in there he shows up with 11hp.
What am I missing?

Here’s a link to my character sheet: https://ddb.ac/characters/31270418/bpyQtf