When you put special characters into the name (like '&' or '>') they will be shown right within the group settings. However if you go to the group overview when you can add/remove users the group name is displayed wrong: the special characters are shown like functional characters ('&' as '&amp'; or '>' as '&gt'; ) - check screenshots.

If you use '<' (less than) in the group name and save it, then it won't be even included into the name (also every other character which comes after).

It would be great if special characters could be displayed normally.

Similar behavior: https://tracker.moodle.org/browse/MDL-62307.