This happened to me twice on the same day. I had 1500 rounds of reloads, we had shot about 900 rounds and then the first squib happened, didn't think to much about it and I treated it like any other malfunction, to get my gun back In the fight. After I looked, tap, racked and the round wouldn't go bang I canted my glock almost 80 degrees and noticed the barrel was 1.5mm out of battery. I disassembled my glock and found a squib not too far into the barrel but nothing too crazy to scare me, so I dropped in my replacement barrel and keep shooting. With in the next 100 rounds I had the same problem happen again. Overall, I finished shooting the reloads and didn't have any other issues but now I don't shoot reloads and if I was shooting reloads I will not practice malfunction drills.
Glad everything worked out for you.