That page *really* does not like to have an iframe in it. I do not think there is any way to fix this other than disabling LSR (for that site). I have amended https://github.com/jaatroko/link-status-redux/issues/7 to mention also this type of issue(s).

(As a side note, that page takes forever to load even when it works without any addons enabled, hurrah for the modern web I guess...)