What I mean by locking up is this:
A hitch must be set to prevent a fall after releasing. E.g If you climb hand over hand above the hitch, then pull through the slack and let go - the hitch should grab. Many climbers, especially competitors, deliberately set the hitch alittle loose to self tend and avoid locking. If the hitch is tied snug to avoid failure to grab, it locks when a jump is made ie. pushing out forcefully from the stem with the legs and pulling down hard on the hitch to smoothly pay out rope so as to land gently on the bough.
This is the holy grail of hitch performance; will always bite after slackening, will always release smoothly on descent. No hitch will currently do this during my research.
Until now; I have devised a hitch that will do this better than any other. I call it the 'Eye-Tie', and I'll share it after further testing with different cords.
Give it a couple of weeks.