Strip out copyright symbol from publication dates, as it causes errors in bibliographies

We've noticed recently that publication dates which are preceded by a © symbol in bookmarks aren't recognised as dates when exporting from an Aspire list to a bibliography (bookmarking from OCLC WorldCat periodically gives rise to dates with © in front of them), giving rise to incorrect [no date] statements in the bibliography. See attached screenshots. (Example from this list: https://rl.talis.com/3/brookes/lists/688CC789-895C-3055-2AD6-5FDFB538202C.html?lang=en )

This is problematic for students who want to use Aspire's capacity to generate bibliographies/reference lists; they get an incorrect citation every time this occurs, because dates in bookmarks which appear as ©2023 (for example) give rise to a [no date] statement in the reference.

Is there any way of tweaking the bookmarking process so that © symbols in date fields are automatically stripped out?