Moon Clerics Jerkin - Secondary Bonus not working

[Dredi]

Character - Human, male, Cleric (7) (Lawful Good)
Item "Moon Cleric's Jerkin" (See image)

Item has a secondary bonus providing a +1 effective caster level and it is alluded to in the description, however when tested with stone-skin (The benefit that should be perceived being +10 damage absorbed) the maximum absorption amount was still 70.

Log and item description in Image

https://imgur.com/a/fNpKd1E

secondary test: Darkfire. Darkfire at level 8 goes from 1d4 damage to 1d6 - Confirmed damage is still 1d4 when cast by a level 7 with this item equipped