It appears that on Motorola Droid (or Android 2 in general?) Gmail pulls and pairs messages into conversation based on a subject even if they are in Trash.
When you receive two shopping list emails in a row that are very similar then Gmail will "quote" the lines that appear in both messages. This seems to cause the problem.
Normally, you shouldn't be getting two very similar shopping list messages anyway. It would duplicate your items.
This is currently under investigation.
When your shopping list arrives the notification will light the LED in your preset color. The problem is that your "new email" notification comes a split second after and overwrites YGS+ notification.
Go to Gmail web interface and create a filter that will mark all messages with your predefined YGS+ subject as "read". This way you will not get "new email" notification for this message on your phone.
Do not make the filter to archive them! If you archive them they'll not come to your Inbox and will not be picked up by YGS+.
This is a known problem when you have too many messages in your inbox.
Please label and archive the messages from your inbox.
Find out more information about archiving Gmail here.
Unfortunately we have read-only access to Gmail and we can't mark the email as read or delete it.
You can however create a filter in your Gmail directly to mark all messages with the matching subject as read. Do not make the filter to archive them! If you archive them they'll not come to your Inbox and will not be picked up by YGS.