I've been in the roof systems of a fair number of buildings here in Northern New England with Queen Post Trusses, (typ of public buildings) and I've not run across such a variation before.

I should think it would not behave well over time. Do you know if the Straining Beam (top chord) has deflected? Or is the Tie perhaps stiff enough that this failed to happen.

4 & a suggest that someone might have been trying to redirect load paths ?

Off topic - Do you know if those Knees are just wide thick molded plank, or if they're true knees?

I've puzzled over many such framing mysteries over the years, often the answer is elusive, though the search is always interesting.

Just solved one yesterday, a year long puzzle over some 150 yr old uncut layout. only the discovery of an advertisement seeking bidders, replete with specs, suggests the framer simply let a detail slip his mind, and then laid it out as specified.

As often as not, these little mysteries are like this example, rooted in human error

Sending you contact info for the person who might have your answer.