Not getting con bonus on HP
 

For some reason, whenever I add my hp to my class, it isn't adding the Con bonus. It goes from whatever the con bonus should be to being a "-". The characters aren't undead of any kind. This is on the ipad version, if anyone was curious.

For this type of thing, you should attach your portfolio to your post. Then others can try to recreate it and perhaps dig through the appropriate sources... The desktop version has a way to see the scripts that apply to a given ability score, but I don't use the desktop app much so I can't comment on that.

As Azhrei says... the more info you can give us the better. Attach a portfolio, or give us a screenshot.
What class? Any archetypes, or templates active? What is actually going to a "-"? The CON bonus, or the hps? Is this happening every level?

Support figured out I had an optional rule, Wounds and Vigor, enabled. I just don't remember checking that box.

Something I've seen quite often is that users will find "Ultimate Combat" in the list of settings, and see that there are 4 un-checked boxes available from that book, and they'll just check them all, thinking "this is a book I use a lot, so I want everything", but two of the optional rules in that book - the Wounds and Vigor system, and the Armor as DR system make drastic changes to how hp or AC works, respectively. We've gotten quite a lot of bug reports like this over the years.

I imagine that is exactly what happened. Lol