I am also having the same issue with this. To be very specific about this issue:
Not all of our users are having this issue.
A user has read-only access to a Word Document.
When the user opens the Word Document - it opens in this "Viewing" mode which is indicated in the top right hand corner. You cannot make any changes to the Word Document. If you try to do so, on the very bottom of the Word document, there is a bar that says "You can't make this change because the selection is locked"
Previously - you are allowed to make changes to the Word Document however, you will need to use the "Save As" function and select a different folder destination. This has always been the case for many years and it doesn't make sense on why this is a thing now. It is such an unnecessary "feature" that serves no purpose.
I have updated to the current channel which was released on 1/26/2023 and this is still an issue. I do not understand what is the point of this. It makes no sense.
Please do comment saying "Check if the file or folder has the read-only box" checked. This never mattered in actually editing the file. This only mattered when you were trying to save it.