This was fixed in July with a patch file to DT Register 4.2.2 (https://www.joomlart.com/forums/d/23688-duplicate-add-member-form-for-group-registrations/3), but is now back in DT Register 4.2.4 with the three patch files:
The client could not click on the icon. They could click the radio button, but the "Next Step" would not work. When I tested it in IE, I could "cheat" by selecting the radio button and then clicking on the Register tab - but the form was the same as in the other report - where multiple instances of the form were displaying.
I understand that IE 11 is near end-of-life, but I have lots of US Government clients who are still using IE (I know, unbelievable!). I explained to the client today that Microsoft is ending support for IE and not updating it anymore, but the people I'm dealing with are not able to convince the government tech support people to allow them to use another browser.
If others are reporting issues, and it's still worthwhile to code for IE 11 compatibility, it would be very helpful to my client base.
Thank you,
Ernie