BUG: when I receive my sign-in email, the button's url is broken

I run 3.41.9 since 2 days. I feel this is a bug. A client of mine can’t sign in to our site and I was able to replicate.


When I sign-up or return as a member, I receive an email.
I have to click the button, but the Url is broken:

But when I copy paste the link, it works as expected. As a user, I can sign in:

URL are different





Looks like you have probably enabled click tracking in mailgun?

Yes it was but I never enabled it. I don’t understand why it break suddenly.