ShortDate Format changing for no reason.

The problem is seen in an ISAPI application running on Win2k Server/SP4.

The server ShortDate format is set to dd/MM/yyyy
The date format in HKEY_USERS/.DEFAULT/Control Panel/International/ is
correct too.

I have to process dates stored as strings in format YYYYMMDD (20040420). I
convert them into a string of 'DD/MM/YYYY' using substrings and then attempt
to convert that to a delphi TDate. Every now and then, and only for a brief
period of time the server shortdate format is strangely set to 'yyyy/mm/dd'
so the convert to Tdate fails. I have set up a stress test on the ISAPI
application and with 25 users constantly processing dates only a small
handful fail, the rest work before the failures and after the failures. We
can reproduce this on Win2k Server/SP4 on more than one server ??

I have trapped the exception and written the shortdate format out to a log
file, it does indeed go to yyyy/mm/dd.

Regards
Martin