这让我想起了其他关于邀请现有用户加入群组的近期话题：
- Invitation Links are Only Working for Non-existing Users & Breaking Our Current Implementation
- Issue with Invite Link: "Add to Group" Not Working When "Arrive at Topic" is Enabled
也许这个关于邀请用户测试群组的链接不再有效的报告也与之相关：Join the Discourse User Testing Community - #29 by jordan-violet