I do not know if this related but I have noticed this with boss frames lately, if there are second bosses as in dead mines with the second boss your frames will show up weird until the first one is dead or second one engages you.
Example:
https://i.imgur.com/QFVyfyq.png
Im going to try Mother today and let you know what my results are.
Yes, they are messed up.
https://i.imgur.com/HfcNjei.jpg
I have created a report on GitHub for visibility.
https://github.com/oUF-wow/oUF/issues/458