Can you think of anything you were doing in your save game that could've caused this? Something we've seen in the past, that was recently fixed, was Make a Flirtatious Joke in group conversations was applying Romantic Interest to everyone in the group (https://answers.ea.com/t5/Bug-Reports/FIXED-Romantic-interest-for-everyone-in-group-conversations/td...). Could something like that have been what happened? That was fixed in the 1.16 Patch for Console, but the fix wouldn't have fixed relationship levels with pre-existing Sims. How long have you been playing that particular save? Is it possible that the Sims had that relationship before July 16th (when Patch 1.16 was released)?

Thanks so much for the help