Message in console "Unable to find a character view"

When modifying a token bar linked to a character attribute, before hopening the character sheet, strange things happen. Looking at the console, I see messages like Error: Unable to find a character view Anyone knows what that means and how to avoid such errors in the sheet workers? PS: if anyone is interested, I'm using the character sheet "Chroniques Oubliées Fantasy 2ème édition by Black Book Editions".

An other error message I don't quite understand: vtt.bundle.b4a642656c7fa6c6c8f8.js:7971 Uncaught TypeError: Cannot read properties of undefined (reading 'find')     at b.$scopedSelector (vtt.bundle.b4a642656c7fa6c6c8f8.js:7971:11588)     at MessagePort.<anonymous> (vtt.bundle.b4a642656c7fa6c6c8f8.js:7434:41193) I still get it after removing all instances of `find` in the sheetworker code. So, does anyone know what could raise that exception?

The error disappears if I remove all calls to `.removeClass` or `.addClass`. But when I log the arguments to these functions, they are just plain constant strings, and the objects are well defined. Also, it works just fine once the sheet has been opened at least once in a given session. Would there be a way to know that a character sheet has been opened, so that we could avoid calling these functions when it is not the case?