I had two issues with one of mine (I have several). I lost one hanging on my PFD during a drill in which I was getting back into an inflatable boat, it must have snagged on something. The replacement has been on my vest for well over a year, so the lost one may just not have been fully locked in place within the little retaining holder. I also notice the blade developing some surface rust, tried it out on some webbing and it still worked fine, just something to keep and eye on.

Pete