Hardware technical difficulties experienced at the end of the game (spoilers)

[Mudbill]

Brandon was just a simulation. If I understand it correctly, when he started getting too emotional it ran the virtual simulation "out of memory" you could say, which essentially crashed it. This resulted in you having to boot it up again, with fresh memory and a fresh mind of Brandon.

Since Catherine is running directly onto the Omnitool (and considering the Omnitool probably wasn't made specifically to store personalities), it's likely that it doesn't account for all memory leaks that may happen.

Did you know that there are malwares that can fry a PC by overworking the components? Find a bug or an exploit. Consider that Cath's emotional outburst was an overlooked exception in the software, and it could cause the Omnitool to run beyond its own limits, basically frying itself.

I also don't think the Brandon simulation had any cortex chip anyway since it was just a simulation.