Supplier sites "last update date" -- change to one site affects others

Hi all,

I'm using 12.1.3.  In doing some testing of updates to supplier sites to see what triggers a change to ap_supplier_sites_all.last_update_date, I found that for certain changes, making the change on one site affects many others.

Example: on a supplier with 31 sites, I made a change to the Communication tab of the supplier site.  I queried the table, and only that site's last_update_date was affected.  The same with making a change to the address of one site.

But when I made a change on the Quick Update page (in my test, I typed a value into the Payment Hold Reason field on the Key Payment Setups tab) and queried the table again, I found that instead of 1 site being updated, 15 sites had their last_update_date changed at the same time.  Then, I deleted the value I had typed in the field and saved again, and upon re-querying, only the site that I updated had changed its date.  I continued making changes to this site and others on the Quick Update page and noticed no more odd