My Node-Red instance "looses" labels regularly. Buttons and default nodes then do not have a proper label anymore. A "Done" button for example is then called common.label.done
A restart of the Docker container fixes the issue.
I am using Node-Red v3.1.0.
The error occurs in any browser. Brave and Edge, I just double-checked. A reload of the Docker contained fixes the problem. It then works right way in the same browser tab after a reload of the page.
No errors in the browser. Everything works. I just have to guess a bit what the buttons are.
The environment is English. It is the official docker image.
short of re-downloading the image docker image (sorry is that the right term? - I don't use docker)
if it continues, after re-downloading the image, maybe raise a bug with the team.