Sorry to bring this up again, but having the same issue. Different fog server however. using build 8179.
I created a small group of hosts ~25 and went to the group page, checked the box and it didn’t autofill the form, thought OK, remembering this thread that didn’t necessarily matter. Then went to a host and saw the box was checked to join and the old information that was in there was now gone. I then tried to update the individual host by clearing the fields and hitting the join box, still didn’t autofill, checked the defaults in Settings and that was still there and correct. I believe this was working on SVN5675.
Browser is Chrome 51. (Now that I think about it I think my chrome updated last week sometime)(perhaps chrome issue?)
Tried MS Edge, Works as expected.
Can someone verify my results?