When I am updating Product date for spacial price in magento 2.2.0 then i am face problem Invalid input datetime format of value '01/12/+00201717'
I had similar issue when one user could save and one couldn't.
If you cannot save just:
- Click your user name on the top right in your panel
- Enter "Account Settings"
- Try to change "Interface Locale" to different one ( I change from english UK to english US)
- Try to save product.