I don't have any exclusive inside info, if that's what you mean.
The real problem is the level/amount of combustion byproducts that Toyota/Lexus engines can produce. I'm sure that the actual number of units involved is relatively small, but formed a frequency of incidence that required attention and corrective action.
It's hard to say about the bypass valve. It's obvious that the 8-11 differential pressure that it ranges in is not uncommon, but I don't think any filter's bypass valve is designed to handle the full flow of the engine ..or I should say filter. Take a look at Wix's modular bypass valve (it's somewhere here on one of the dissection threads.
or look here:
Right behind the red silicon ADBV
http://www.wixfilters.com/productinformation/index.html
So, while it may open @ 8-11 psi, it really doesn't look to be designed to handle the full oil output of the engine. With a totally plugged media, this could setup the scenario in question.
I don't think this occurs in all but extreme cases, but does tend to contour the problematic engines that don't just impact Amsoil. The part we haven't settled on (realized, accepted) is that your engine/situation may not have that issue, nor would your service profile, but since it shared a part number with an engine that does, that filter went away.
They're working on a redesign. No telling when it will show up.