Level one character HP too high

So in the character sheet each character in our campain had total hp at level one counted as follows: max hit dice + Constitution Modifier + hit dice roll. So for my Bard it was 8 + 4 (rolled 1d8) + 3 (16 const) = 15 max HP. After leveling i got only 3 points HP from my Constitution Modifier. We chose roll Hit Dice on level option

You can still see the bug on characters that haven't leveled yet. Character sheets:
https://www.dndbeyond.com/characters/47171036 lvl 1 Ranger (14 Const / +2 ) total  14 HP
https://www.dndbeyond.com/characters/47171072 lvl 1 Rouge (11 Const / +1) total 13 HP

This is a known bug. It's caused by you choosing Manual HP type before choosing your class - thereby defaulting Rolled HP (in the Manage HP button on the class page) to 12. Just change the Rolled HP to the correct value and it's fixed.