WebGUI 7.8.20 has been released. This version includes many fixes for groups, including a massive performance improvement of at least 300% for most group membership lookups. 

Full changelog below:

 - fixed #11552: Visitors (and others) can bypass group-by-IP restrictions
 - fixed #11572: visitors can enter editProfile
 - fixed #11563: Syndicated Content - descriptionFirstParagraph cuts off
 - fixed #11538: User invite mail: whitespace in message lost
 - fixed #11549: Shortcut Asset cannot override Page Layout
 - fixed #11576: Default WebGUI config has a bad macro
 - fixed #11578: Collaboration System: add edit stamp uses wrong user
 - fixed #11581: Calendar problems
 - fixed #11583: EMS: Tokens do not follow their permissions
 - fixed #11582: Registering with a .mobi email address
 - fixed #11580: Date not populated for Story Archive RSS feed
 - fixed #11587: Thingy, no fields and undefined statement handles
 - fixed #11589: Syndicated Content: Return raw text for sentence and word template variables
 - fixed #11573: user has no way of knowing what they are currently using