Error log re FavoritesArrayFormatter.php

While searching through my site’s error logs, I discovered this entry:

[13-May-2019 09:21:56 UTC] PHP Warning: Cannot use a scalar value as an array in /home/kw07ff1a1fg5/public_html/gwizproductions/research/wp-content/plugins/favorites/app/Entities/Favorite/FavoritesArrayFormatter.php on line 73

The Favorites plugin seems to be functioning well otherwise, but given that I have a few ten thousand posts that display favorites, this makes for a Really Large Error Log.