It is possible to change comments that are not made by myself. For example, the formatted dummy text from https://extensions.libreoffice.org/en/extensions/show/132 contains comments authored by "LibreOffice Design Team". Modifying these comments is accepted and does not change the author. We should either block it completely (to remove and to resolve should be enough) or at least add a not "edited by <>" or modify the author. By the way, MSO has the same problem.
Although blocking should be correct, it is always possible to do it by editing the file. Perhaps adding a remark with the last editor at the end of the comment text, and replacing it with the current one.