Zeni reverted the chat API today. Many addons that leverage LibChatMessage are acting strangely and/or throwing errors. You can fix this by installing an older version of that library.
I confirmed that the June 2019 version restores functionality to my addons and resolved UI errors: https://www.esoui.com/downloads/getfile.php?id=2382&aid=28005
Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, the abyss gazes also into you. ~Friedrich Nietzsche