std::time_get<>::get_date() is required to be able to parse the output produced by std::time_put<>::put(..., 'x'). For some locales, the '%x' format specifier expands out to '%e.%m.%Y'. When a date is formatted using this, there will be a leading space, and that leading space causes the time_get<>::get_date() operation to fail.
The root of the problem is that the POSIX strftime() function [which we emulate in time_get] requires that the '%e' specifier generate whitespace for single digit monthdays, and the POSIX strptime() function says that the number may be padded on the left with 0s. It does not appear to specify that whitespace is allowed. The strptime() implementation on some platforms [sun, linux, compaq, aix] allow this whitespace, while others [hp, freebsd] do not.