Core Stone Gives Up (Bug or Feature?)

I'm like 90% sure the janky terrain of the room caused the rifts to be unable to spawn, similarly to how a Lithophage Meteor will self-destruct if there is no suitable terrain for the rock crackers to land on.
Or maybe me flipping my weapon at the right time while having 45 mods active had something to do with it ¯\_(ツ)_/¯ who knows.