email links with subject= no longer work

I have a number of mailto links with subject to help the recipient know how the contact was initiated – see above page. The mailto link get protected, but the ?subject=…. now gets munged into the email address, so the link so longer works. This used to work. I tried different settings and different email clients. also tried generating a link directly as html link This too gets protected but the result is the same. Seems ? in the string is being filtered.

The page I need help with: [log in to see the link]