I almost forgot to mention something else that happened.
I went into edit mode in OL (when my sims were in the present) and made some changes to their OL house. (I got rid of all but four of the rodents, and made some other changes in harvestable placements, to correct routing errors.) I went back to the present game and saved.
But when I initiated time travel with my female faerie sim (who originally purchased the OL house) to go back to the future, the family was sent to Emit's house. I sent them back to the present, and then back to the future, again. Same problem.
So I had my female faerie go to the house property, which still showed up as owned in her real estate records, and then I went into buy mode and got a time travel portal for them, which I placed on the OL house property lot. I sent the family back to the present through that portal on the OL house property.
Then I had my female sim initiate time travel to the future, again. When she did, I got the expected popup to choose the purchased home and the family arrived at their OL home without a problem. But instead of teleporting in the way they used to, the family used the portal on their property to arrive. I saved my game, and things have been working fine, since then.
I thought maybe anyone who is experiencing difficulty getting back to their purchased home might want to try doing what I did. (I would be interested to know if that works for other people.)
And I would have to advise that using edit mode in OL to edit an existing purchased home should be done only in emergencies, and with caution, because it seems to break ownership travel links.
edit: My light instrument reverts to orange when I try to set a unique play color. I've tried purple, white, and blue, but it always resets to orange. I haven't tried to change the green idle color.