Originally Posted by
f4rrest
That's happened to me once or twice. It means the core itself was already loose, so it's better to find out about it this way.
I don't have replaceable valve stems so I can't comment on that. But if that is the case and someone uses replaceable core then obviously that should be considered and the Topeak would be the better pump since it doesn't screw onto the stem. If you had that issue maybe Lezyne should be told about it and see what they say.