Method to recreate bug:

Create a feedback form like this:

{CGFeedback key1="Pages" key2=$page_name titlerequired="0" emailrequired="0"}

Note emailrequired="0" - I don't *require* people to enter their email address,
it is up to them.

Submit some feedback by filling in the feedback form.  Enter "NoEmailHere" (or
any text that is not an email address).  Tick the box to notify you of any new
comments on the page.  Press submit.

(Yes, I know it is silly to ask to be notified but not give a correctly formed
email address....but users are sometimes silly...)

If your system is set to "Modererate all comments" as yes, then go to Calguys
Feedback Module and mark the comment as published.

Submit some more feedback, doesn't matter what.  This forces the CGFeedback code
to go through and send email to people who have asked to be notified about new
posts.

A message appears just above the message about successful submission of the
form.  Some text shows for each failed email in the system, in this case:

"Invalid address: NoEmailHere You must provide at least one recipient email
address."

Presumably this is where some code is crashing when trying to send an email to
NoEmailHere.



NOTE! There is also a security issue here, since whatever was typed in to the
email address box by previous users is displayed on the site to future users.
This is why I marked the severity as Major.