The following seems to be a bug of FORMAT.

> (round 1.23e20)
1.23e+20
> (format "~0,3F" 1.23e20)
"1.230e+20"
> (round 1.23e-20)
0.0
> (format "~0,3F" 1.23e-20)
"0.000"

--
INITERM