I can only think that Biela has changed the size that they manufacture to.
This engine isn’t new to me and was in my Hangar 9 Corsair for three years previously, first with a 22 x 10 3b semi scale Biela, then 22 x 12 3b and lastly the 24 x 10 2b.
The 2 blade is the thickest at 34mm.
22 x 12 3b is 28mm
22 x 10 3b is 27.2mm.