After updating to version 34 of Home-Assistant the following error showed up in my frontend UI.
I’m bad at reading release notes and it worked, ish, so I ignored it.
After a few days it did started to itch so I started googling, found this issue: https://github.com/home-assistant/home-assistant/issues/4726
And behold the solution:
Thanks, timstanley1985 & exxamalte, next time I’ll try to read the release notes before updating 😛