A Seraph has 4 on strength cap naturally.
When you select "Physical" as your background, it gives you "+1 Strength"
When you select "Strong" as your trait, if gives you "+2 Strength"
You'd think "Ah, I start with 3 str! Sweet!"

What actually happens is that backgrounds affect caps. However, the in-game side doesn't say that-- as you can see in the images here

https://imgur.com/gallery/xzqN30c


It might be good to change the background descriptions to "+1 Max _______ " rather than "+1  _____"