Its same brand, model, batch of tubes. both blew up close to but not exactly at the vent.

The second time around, I filled up the tube, then let the air out and only then went about putting it back on the wheel. Should I put it in the tire and on the wheel with more air? As you know it does make the process a bit unwieldy. Once back on I did fill it up to 40PSI spun it around : seemed fine. when I pumped it to 115 PSI spun it around again: I saw no protrusions/ pinches...

I am not trying to be defensive. its just I have only one more tube left and I'm not really sure how I can possibly be more careful than last time.

BTW guys many thanks for responding at that ungodly hour.