We've all done stupid shit. Had this happen to me a year or so ago. No powder, luckily, it was only one round. Since then, to be sure, I use a small LED penlight to inspect all of the powder dropped rounds in the loading block. Hasn't happened since.
Last Tuesday, I was shooting my 40XBKS and had one round not go off, I thought, not this shit again. I tried it a second time and it went off. It was an older lot of the original Russian "Wolf" LRP's. I shot off all of the older Wolf primers and I'm using the newer Tula branded primers. I did have 2-3 dud primers in that first batch of 1000 Wolf primers. No duds yet on the Tulas.