Christian, I have a used foam seal for you if you want it. It seems completely fine.
I bought all of my bearings online, all with their matching races of the same brand. Mixing & matching manufacturers "should" be okay but I don't trust that. I'm not sure what you have but sorry that it happened. I bought my seals from ET just because it's not worth the risk of a one-lipped failure. I doubt that was your problem though.
Guesses: An under-lubricated bearing would get hot and self-destruct, which was not the case here. An overly tight bearing would get hot but may not destruct thanks to good fresh grease. The grease might liquefy and find it's way out, though I'd expect the seal to hold anyway. If there was enough heat to raise the air pressure inside the hub to the point of blowing out a bit of grease, well... that seems pretty unbelievable, but maybe possible? It could only happen at the inner seal as the outer has the bearing cap, nuts and washer.
These things are so touchy, and a pain to get torqued with that stupid nut tool without it slipping out of the grooves. Then the bearing seating & clearance issue... not one of the most fun G repairs.