MacMail does not like Firefox browser

I have been using Firefox since forever. I think that with some sites it is better. I do not remember.

I also use MacMail with my Comcast Internet. When I have a link in a mail, clicking it opens Safari. Which is OK. If I want to have the story (WaP0) side by side to DU, I just open another tab on Firefox and copy the URL from Safari.

Except something bizarre happened today.

I have an account with Vanguard. I talked to a rep last week and received an email asking for feedback. No problem, he was knowledgeable and helpful. But when I started the survey it sent me to Safari where I was warned that the site was unsafe, may try to get personal information. I got out of course.

But then... the browser on my iPhone is Safari, of course, so I opened that email there and got to the survey with no problems.

Curiouser and Curiouser