My character is using Elven Chain. Going by Paizo, the max dex limit is +4, but it only shows +3.
I can't reproduce this, and it looks like you hit medium encumbrance, which gives you a maxdex bonus of +3, an armor check penalty of -3 and limits your movespeed. Can't tell without a complete character though.
AS pointed out, this appears to be Encumbrance enforcement rule.
There is nothing to fix. Supply the character file and I'll show you why the numbers are not how you want.
Close it. You're right. It is encumberance