I get the following error ...
ailed to load resource: net::ERR_FILE_NOT_FOUND (file:///Applications/Joplin.app/Contents/Resources/app.asar/gui/note-viewer/:/f737eb7e06484500bfdf05f4caade75c) but the file is available in the webdav .resources folder.
That could be a bug! :/f737eb7e06484500bfdf05f4caade75c is an internal Joplin resource/note URL and file:///Applications/Joplin.app/Contents/Resources/app.asar/gui/note-viewer/ is a file path (they shouldn't be joined like that).
Can you give some context about what you were doing when the error happened? Are you using the rich text editor or the markdown editor? What is the markdown for an example note that has this issue?