To recreate: - change the dateformat syspref (I was on MM/DD/YYYY and changed to YYYY-MM-DD) - click to edit a patron record - select yesterday for patron's date of birth - note the text that appears under DOB to tell you the patron's age is something entirely wrong This is only an issue with the age as it appears on the edit page. Koha calculates the age correctly on save and correctly enforces category age limits. Dateformat is getting cached somewhere. I was able to correct it by restarting memcached and plack, but that shouldn't be needed.
dateformat_pref is a global variable and does not seem to clear until a restart_all