[d1sxeyes]

It's not required, you can re-use the exact same glyph. The letters are effectively the same (both descendants of the Greek 'alpha').

Generally when this happens, it's because they copied the Latin glyph and then made some tweaks to the whole Cyrillic alphabet to make it look more even, etc., and the changes to the 'a' may not even be intentional, but the 'a' got caught up in a batch change or something.

[account42]

Could also be that both were traced/vectorized independently from the same source. Still, you'd think that a competent digital front creator would recognize that the glyphs should be the same and store them only once for both characters.