compare code revisions not working

Thank you for this life saver plugin! It really does the job.

But we’ve never been able to use the “Compare” option within code revisions.
When we push the “Compare” button we get a 404 error.
Here’s an URL we get as an example (domain name has been changed)

https://www.domain.org/wp-admin/edit.php?post_type=wbcr-snippets&page=revisions-wbcr_insert_php&snippet=36279&from=36299&to=36300

The correct URL should be:

https://ww.domain.org/wp/wp-admin/edit.php?post_type=wbcr-snippets&page=revisions-wbcr_insert_php&snippet=36279&from=36299&to=36300

It appears the “/wp” is missing. Any idea or lead why the calculated URL isn’t correct?

Thank you.