It may just be a coincidence, but I found two videos that involve the 767-200's speedbrakes not deploying automatically upon touchdown (which should occur if they are armed).
The first video shows the speedbrake lever move less than an inch upon touchdown, then the pilot flying extends them all the way.
The second video shows the speedbrakes not deploying at all for at least 5 seconds after touchdown, then they extend in incrementes until extending fully a few seconds after that.
Does the 767-200 have some sort of "quirk" when it comes to its speedbrakes deploying, do some 767s not have an "armed" function, or are these just coincidences where they failed to automatically deploy?
P.S. I also have this footage of the 757's first flight where the speedbrakes clearly do not deploy automatically, either.