This is almost certainly due to floating point fraction behaviors, since 0.9 doesn't have a precise binary representation. (Repeats in binary, much like ⅓ repeats as a decimal.)
Possibly exacerbated by this related phenomenon:
This is almost certainly due to floating point fraction behaviors, since 0.9 doesn't have a precise binary representation. (Repeats in binary, much like ⅓ repeats as a decimal.)
Possibly exacerbated by this related phenomenon: