I was sure we had this one resolved but I've spotted another occurence of this problem on this site, where the date defaults back to 01-01-70.
If you sign into the site with the user information provided below and select order ref 3835, you will see six tabs across the top:
Certificate / Step 1 / Step 2 / Step 3 / Step 4 / Step 5
Each of the "Step" tabs has an "Edit & Save" button at the bottom.
If you go to Tab 1 and click "Edit & Save", it reverts the date back to 01-01-70, however this doesn't happen if you select the "Edit & Save" button on any of the other Step tabs.
Can you see why this is? FTP details provided below also.
On an update form, should the defaultDate be null in the datepicker script, considering that value should be being populated from database?
Could this be the cause of the 01-01-70 issue?
Commented out the defaultDate: null line in the script and now it's saving the date as 04-08-01!?