I agree that it sounds like a military op, but why assume it was the Russians? This was a civilian station. If it had any sort of listening/detection capabilities those would be a threat to all military operations, irrespective of national origin. The americans, the brits, the germans, the russians, any one of them could have taken issue with this rig.

But I think it far more likely that this was a military accident. Someone dragged an anchor, net or towed sonar array over this thing. They might not have appreciated what had happened until days/weeks afterwards.