Nope, don't have experience with it. When you say "you are expecting", are you implying that I'm expecting something I shouldn't? If your effective timezone right now is GMT+0 you won't see the entire effect I'm seeing. And someone else tested XP and saw the same effects I was describing earlier, except it was doubling their GMT offset instead of mine.
//var -s %a Jan 01 12:00:00 2019 | timeapi off | var %aoff $ctime(%a) | timeapi on | var %aon $ctime(%a) | echo -a $calc(%aon - %aoff ) | var -s %a Jun 01 12:00:00 2019 | timeapi off | var %aoff $ctime(%a) | timeapi on | var %aon $ctime(%a) | echo -a $calc(%aon - %aoff )
There 2 effects going on, and I'm not sure that $asctime can be blamed for both. The 1 hour offset seems to be a problem in $asctime(N) where it never transitions on/off daylight time. However the above code doesn't use $asctime at all, and it's showing a 1 hour effect.
When clock is set to USA Central with the current date during daylight time, the GMT offset is -5. The above snippet shows -39600 then -36000, or -11 hrs and -10 hrs. When clock is set backwards 1 month to be in standard time where GMT offset is -6, the results are -43200 then -39600, or -12hrs and -11hrs.
So it looks like there's a 1 hour issue in both $asctime and $ctime, as well as a doubling of the GMT offset for $ctime(string)