36 is what a d10 hit die character will have at level 4 if they take formal average each level and have a +2 constitution.
(10 + 2 at 1st, then 6+2 at 2nd,3rd and 4th = 36)
I don't recall any of our EA characters breaking 40 at any point under the various patches or versions, and the numbers they arrive at have always been the same, so I'm fairly certain that that is what they're doing.
The opposite to this is that *enemies* don't play by the same rules, under Larian.