Got_Lumens
(Got Lumens)
249
It sounds as if something is preventing You from completely tightening the tailcap while the clip is present. I’m sure when You find the time to troubleshoot and disassemble You’ll get it working just fine 
Maybe the o-ring needs to be a tad larger with-in your lights build? Not sure. Maybe talk PM with others that have the Ti/Copper version ???
Hope You can get yours working properly