In short, if a username or display name does not pass roblox’s filter. you cannot invite them to individual team create projects. the search screen just stalls indefinitely.
Step 1: Find a user whos username triggers roblox’s chat filter. my example is “bird13895300” (I guess the string of numbers makes roblox go “AHH, MIGHT BE A PHONE NUMBER”)
Step 2: try to add them to a team create project by username
Even if you try to search them by display name or UserId they’ll be excluded from the list.
I expect to be able to find users of any username to be able to add them to my project.