Rocket lower stage flying up through payload

[RocketSquid]

For reasons unknown to me, the lower stage of my rocket has decided to, on multiple occasions, fly upwards through the upper stage and payload, thus destroying the rocket. I was using parts from DSEV, Buffalo, Pathfinder, Tantares, MH, BG, and Tundra Exploration. The rocket seems to do this, not in response to any particular conditions, but rather a fixed amount of time after launch, whether it’s sitting on the pad or already out of the atmosphere.

 

EDIT: Something is creating an enormous number of NREs in that particular save, but none of the others. Is there any way to figure out what’s causing that?

Edited June 5, 2019 by RocketSquid