Looks like its the 1L monster brew bottles causing the problem then. Send em back.
the solution was:
"Figured it out, the stopper thing in the case I just opened was slightly smaller and they work perfectly.
The first case has the wrong stoppers included, would have been nice to know before breaking a **** load of them and injuring myself, but it is what it is."
Id be pretty angry that this is happening more than once and they arnt solving the problem and customers are getting hurt.