I think "ctime" and "asctime" are supposed to wrap or imitate the standard C functions: <https://port70.net/~nsz/c/c11/n1570.html#7.27.3.2>, so I think this is intended behaviour. But see Issue 13927 about improving the documentation.

For a single-digit day of the month, there is supposed to be two spaces. Using "%.2d" would produce "Sep02" or "Sep 02", with a leading zero. On the other hand, changing the double space to a single space would produce "Sep 2", without a leading zero.