Adding tags to a contact does not always update the updated date

Hi,

I am using the API to get a list of recently updated contacts (i.e. those that were updated after a certain date/time) and I'm finding that under very specific circumstances, if a tag is added to a contact it will not update the updated_at field on the contact.

This non update happens when:

• The contact does not have a postal address nor a phone number
• The contact is updated from the web interface when you are looking at the contact detail, click on Edit, select a tag from the list, do not update anything else, and click on Save.

The updated_at date updates correctly if there is a postal address or phone number. It works if a tag is removed instead of added. It also works if you select the contact from the list, and add the tag from the Actions menu.