Unable to kill spiders spawned from chests

I had multiple strong boxes open next to one another, One being a unique strongbox "swarms of things". Killed everything box despawned. Opened the next box near it, revives nearby with onslaught. It revived 8 little spiders that are immune to any damage, and/or not targetable. unable to proceed with clearing the strongbox due to these bugs.. literally.

Bug reference number 2,130,426,906