We have very basic notification rules implemeted. When an issue is assigned to a user, they receive an email.
When an issue is created, the reporter rececieves an email. Thats it.
For any items assigned to or reported by a user "outside" of the company (email address not on our domain) the user receives 8 emails.
This is the reason we trimmed notification down to such a minimal rule.
Any internal users dodn't experience this issue (unless they are watching the issue). If watching, multiple emails are sent out for each edit.
Thoughts one what could be causing this?