2019 389 x15 shutting off during heavy braking

I have a 2019 389 with 250000 miles on x15 that has shut down three times since buying truck 6 months ago. Always during a heavy braking situation. Truck will shut off with no codes. Will allmost start when first start cranking then just cranks. First time it happened it got towed to dealer. The batteries died before they could look at it so they recharged batteries and it started right up. They said probably just bad battery. I didn't think it was batteries so drove it for couple months before it did it again. Same crank no start. Unhooked battery cables for 2 minutes and it started right up. Thouht maybe couldbe bad cell in battery so put three new ones in. Ran another month and did it again. Unhooked batteries and started up. Has anyone had something like this happen? Thanks

 

All electrical power stays the same just shuts engine off. Something is not allowing it to start until rebooting it by disconnecting batteries. No codes have shown up on scanner