Could be that Biryukov is using Torx Plus instead of Torx now.
View attachment 1969020
As an example, a T8 driver will fit into an IP8 socket--Inside Plus is the Torx Plus designation--but feel sloppy while the same size IP driver will not go into a regular T socket of the same number.
On the other hand, some cheaper screws can have socket heads machined outside of standard tolerances.
Checking my Biryukovs for any Torx-style screws, only my #9 liner lock has any of that type fasteners, attaching the scales, while my other two--frame locks both--have only his proprietary 3 lobe pattern fasteners. The #9's scale screws are regular T8's, and a good fit at that, but I believe that knife to be one of his very early folding models.