I just tested the glitch as well.
On April 16th I adopted Marshal (my game was April 21 since I had TT'd to move someone out). He gave me the repeated dialogue. I invited him the first time and said "don't know" the second time when he asked where he should move. After he moved in and was out of boxes, I TT'd back to the present day.
I then quarantined my game (no visitors/visiting, but still sent online mail with friends) until today. My friend came over today, and Marshal was in his house. We had a connection error so nothing saved, but after, Marshal was wandering around my island. He's back over now, and Marshal's gone back inside his house but still normal. I guess if your would-be-glitched villager has made it this far it doesn't seem likely they would glitch out now? Although I have read people checking their game and the whole house is gone and an empty plot remains...
On April 16th I adopted Marshal (my game was April 21 since I had TT'd to move someone out). He gave me the repeated dialogue. I invited him the first time and said "don't know" the second time when he asked where he should move. After he moved in and was out of boxes, I TT'd back to the present day.
I then quarantined my game (no visitors/visiting, but still sent online mail with friends) until today. My friend came over today, and Marshal was in his house. We had a connection error so nothing saved, but after, Marshal was wandering around my island. He's back over now, and Marshal's gone back inside his house but still normal. I guess if your would-be-glitched villager has made it this far it doesn't seem likely they would glitch out now? Although I have read people checking their game and the whole house is gone and an empty plot remains...