Wow, sounds crazy.

I like to seat my tire before putting sealant in it. I pump it high, let it pop onto the bead, and check to see that it is evenly seated before going further. Sometimes they have a difficult time seating correctly all the way around.
(of course skinny strippers make it easy to get a good air seal and harder to blow off when initially installing the tire, blah, blah, blah...).

Be safe out there. At least the blow offs always seem to be on initial install. That could put one in the hospital if you were on the road.