Tashkent is probably just a location where Bokhara-made beads are offered for sale.

They only enter the discussion because they are often similar-in-appearance, because they are also simple furnace-wound glass beads.

Also, I have seen more-recent beads attributed to the region, that were rather more-well-made. So perhaps these very obscure beads persist and are improved. By the time I saw the online offering, the beads were taken.