[ano]

We tested the nearly identical situation and Golem did cast returning successfully. Same artifacts, same gems, same script, same situation. I played with PD (from 0 to 40) and gems but always had the same result - golem did cast returning the first turn.
So probably this is a very weird and badly reproducable bug.
That golem was worth about 100 gems total (taking on account forge bonuses and not taking on account forge time and the fact that these artifacts can easily be reforged). And as it happens not first time, I think, it should be investigated by the devs.
I can provide anyone interested with the turn files and description