When you visit a group page, then click on a member profile, you can’t use the back button to get back to the Group Page. It does work if you go to a post, you can use the back button to get back to the group page, you just can’t do it after clicking on a member to visit their profile.
Steps to Repo:
Visit a Group Page
Click on Members
Click a Member to visit their profile
Click back button
You are left on the member’s profile page
You are taken back to the group page.