We have a custom date attribute that has stopped working correctly, it is set for indicating a new user's start date in an account creation form.
This is then used to generate a username automatically for the user with the below code;
%firstname:lower,1%%lastname:lower,2%%adm-CustomAttributeDate1:format[ddMMyy]%
ie.
Homer Simpson with a start date of 09/03/23 would generate the username hsi090323
however the formatting rule is not followed, there is not 2 digits for the day or month and the time is always included;

Is this by design or a flaw? should i now create the code a different way to get the result i need?
Also the date is the wrong way round, the server is set as a UK date/time format.