Reading between the lines of the article it seems advanced but not too surprising.

I assume that at night when it "withdrew to a covered location" there was opportunity for maintenance, battery swaps, etc.

The article says that it successfully carried out "multiple calls for fire." That sounds like over those 45 days there were multiple missions to provide suppressive fire. They're not explicit about what that means but it sounds like, "if you see anything moving in this arc, take a few shots at them". Presumably there's some AI to prevent it from wasting ammo on really dumb decoys.

A "simple" mobile automated turret has been around for a while. The novelty they would be demonstrating is essentially battlefield robustness. They aren't claiming that this machine can operate completely autonomously for 6 weeks but the incremental pieces are still hard.