1. Which action do you use
2. Get ensure that everyone can read the group members (It is a common failure, that the groups are configured the only group members can see all members of the group)
Have you looked at the user profiles in SharePoint? Is everything fine with the detail in there, i.e. email addresses. When you send a email to one person, do you use the email address or the people picker functionality to choose a person? Have you tried emailing to more than one person without using groups?
the links like modified by, current item etc.. seem to be causing the issue. looks like there are bugs on the links when we add groups. It doesn't notify to the group.
The hyperlinks are not working correctly. Whenever I enter them it breaks on the email. this is really annoying my friend.
What hyperlinks are you referring to? Is this in the emails that you are sending? Can you send some more examples or screenshots of what you are experiencing?