For all practical purposes, the Eclipse series was BM's first entrance into the realm of mid-lock, lockback folders comparable to the mechanism used on Spydercos and Al Mars (the originator of the mid-lock if I'm not mistaken). The original design was intended to enable a rockerbar-lockback to be easily closed with one hand, while still retaining the strength of the lockback design.
What's likely going on with the failures you're experiencing is that in BM's efforts to enter into this foray (though it is not their first lockback, but indeed their first mid-lock), they messed up in one of two ways if not both. Either the blade tang channel or the rocker bar hook is too shallow for effective locking under stress, or the spring exerting pressure on the rocker bar is too weak and is buckling under the stress of the spine whacks. More than likely it is the combination of the two elements that are causing your heartache. My suggestion is to cut your losses, treat your knife as if it's a slip joint, and get yourself either a mini or full sized AFCK with an ultimately more reliable lock and superior features in general. Then there's the axis... don't give up on BM because of one dud. I really think they've got the best knife for the money.
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Professor
Ever notice no other candy tastes quite like Pez? Oh yeah, and the BM Axis rules.