You put the primer in sideways.
I bet they were really hard to push in and you just never noticed they were in wrong. I've done it before with those little hand primer tools. Especially the Lee.
I think if you pull the bullet you'll find the powder in the case is fully intact and never ignited.
It doesn't matter if you put cake batter in the shell if you have the primer in sideways or upside down or what you were shooting at nor what any thing else you shot or didn't shoot.
It is plain as day that primer is in wrong to any one who has ever seen it before.
Pull that bullet and you will find the case full or empty of powder, but either way it will not be burnt.
Then resize the case and knock that primer out and you will see it was put in the pocket wrong and there is NOT a hole burnt through any thing.
^^^ That right there is most likely spot on.I can't get the picture to blow up but that primer looks all sorts of wrong, I think that one was a primer issue and agree if you pull the bullet the powder is going to be intact and never got ignited.