Tire bead ripped, what am I doing wrong?

My brand-new Continental GP5000 tire, along with a fresh tube, just blew up while I was inflating it. The tire bead tore apart.

Since I had some bad luck with tubes, it took me several attempts to mount the tire properly. To help with seating, I used some soap, and everything seemed fine. However, the tire didn’t even tear at the spot where I last mounted it, which makes me wonder what went wrong.

Any idea what I might have done incorrectly? I’d really like to avoid wasting another 50€.