many breadcrumbs displaying current page as link

[StephDriver]

Describe the bug
Breadcrumb at top of page is showing current page as a clickable link, which then refreshes current page.

To Reproduce
see example at [journal]/cms/
sitewide issue

Expected behaviour
Breadcrumbs should be clickable for higher levels, but current page should be plain, making clear that it is the current page.

Screenshots
Example of correct breadcrumb at [journal]/publish/

Example of incorrect breadcrumb at [journal]/cms/:

Additional Context

breadcrumb investigation grew out of issue #3797
More pages affected than unaffected. Details will be clear from the commit(s).