Hello shannonr2,
If this is the only place this happens, it indicates that there may be something in that thread that is causing an issue.
We have some possible solutions for you.
First, try changing the group photo and see if that stops the notifications. Use these steps found at Name a group text message on your iPhone, iPad, or iPod touch:
Tap Change Name and Photo
The Change Name and Photo option is in blue text under the group icons and names of the people on the thread.
Remember, you can name group iMessages, but not SMS/MMS group messages. To name a group text message, everyone needs to be using an iPhone, iPad, or iPod touch.
This should resolve the problem.
If by some chance the issue continues, have the other members of the group do the same.
The next step, if the notifications continue, would be for everyone to delete the group thread from their devices, and use the steps at Send a group text message on your iPhone, iPad, or iPod touch to start a new thread.
Have a good day.