[Edi]

Interesting. I'll distill this into a proper shortlist entry later.

Monster 602 has certain attributes that only appear on pretenders, namely pathcost and startdom. You probably need to get rid of both attributes to remove it from the pretender list. If the first shape of a shapechanged unit has god attributes, then so does the second one, which is hwy it probably appears in the pretender list.

Shapechanging creatures have a number of potential issues when made pretenders. One of those for example is the cost mismatch bug, where choosing the shapechanging pretender means that the point cost is calculated on the basis of the other shape that is not shown (which is why some gods did not work earlier as intended, e.g. the Dracolich, see early shortlist entries).