I've opened an InDesign document from earlier this year (created in an InDesign 2023 version). The document contains many incopy assignments - some of which are now missing. It will let me delete most of the missing assignments (no longer needed anyway) but a selection of them will not delete at all, and show the pencil icon that says 'in use by me' when i hover over, despite having literally just opened the file and not clicked into anything.

This happens when any of my team open the file (we use Microsoft Share Point to access files). I can't right click and 'Go to Content', or 'Unlink Content' because nothing happens, I can't use the trash can icon because again, nothing happens. When I right click and choose 'Add to Assignment' and create a new assignment (or add to existing assignment), i get an error message saying 'The story format is not compatible with this assignment.'

I am not sure how to fix this, if it is a bug? I just want to delete all the broken assignments because they are no longer needed. We are now using InDesign v19.0.

Thank you