[Autumn]

It seems that the +20 stat mod cap was somehow removed recently, either that or I'm reading this wrong, a BK/Hexer with upwards to a +25 DEF mod, obtaining it in full.

Mods used:
Walk in Darkness +3
Galren +4
Astral Belt +5
Castling +7
Iron Wall +6


Sanguine Crest is also granting something around 10-12 DEF if that counts, but I don't think it does count towards the mod cap normally.

[Neus]

The +20 stat mod cap only applies to enchant-based bonuses. Passive class skills are a class modifier. Sanguine Crest is a race modifier.

Galren, Astral Belt, and Castling are enchant-based bonuses, which are under +20.

[Sawrock]

Do items count towards enchant-based bonuses, or are they a separate item-based bonus?

[Neus]

Item bonuses are enchant-based effects.