Check out if using << Use Locale() helps at all.
JMP was fairly bad at managing managing time (and dates) before JMP16. I would most likely parse the string to year, month, day, hour, minute and second. Then sum those to get date_time. With JMP16 you could most likely just use Format Pattern
Maybe this can give some ideas:
Names Default To Here(1);
str = "2022-10-22 16:25:37";
date = Word(1, str, " ");
time = Word(2, str, " ");
y = Num(Word(1, date, "-"));
m = Num(Word(2, date, "-"));
d = Num(Word(3, date, "-"));
time_separator = Left(Regex(Format(Today(), "h:m:s"), "\d", "", GLOBALREPLACE), 1);
hh = Num(Word(1, time, time_separator));
mm = Num(Word(2, time, time_separator));
ss = Num(Word(3, time, time_separator));
date_time = Date DMY(d, m, y) + hh * 60 * 60 + mm * 60 + ss;
AsDate(date_time);
-Jarmo