A very minor and rare bug... or at least I think it's a bug, perhaps it's intentional. I arrived at an unexplored system the same time as the Moltar, there was a space monster present. Apparently the Monster attacked the Moltar as it didn't engage my ships, this in turn allowed me to explore the ruins that were present, something I would not have been able to do had the Moltar not showed up on the same turn. Autosave is attached, as well as a manual save showing my search of the ruins.
I'd say it's a feature. The monster got distracted with the Moltar and you snatched the ruins in the meantime. Thanks for sending the saves in any case.
Works for me, I can live with that. It's a rare thing to be sure, may as well leave it in and let the player be pleasantly surprised from time to time.
Unless it choses the player, that would not be nearly as pleasant, lol. Maybe the monster saw it was you and decided to be safe.