Just had two ion cannons fire at the same nest, because the blast from the first revealed another spawner in the split second before it was destroyed.

Okay, watching several more firings, I think what happened isn't that the blast revealed another spawner, but a second radar did. Maybe some check for if there's already a strike ordered for the area?

the radar does not matter,there is only one event when a new sector is uncovered.
but I keep it in mind in case I work on the algorithm.

I forgot to follow up on this:
What I now think happened is that the nest in question bordered two chunks, which were both revealed in quick succession.

I am sorry. I don't have enough resources to add new features at the moment.