After reading the rMail, it still shows "new rMail" in bold red on the homepage, and "rMail" in bold light blue at the top right of the page.

This persists even after I deleted the rMail.

On other pages the "rMail" at the top right of the page isn't bold of light blue, just the normal link blue; but when I go back to the homepage it still shows unread.

May it be because there were several people addressed via a group, and they all need to see the replies?

This sort of thing is usually caused by deleting an rMail without reading it first.

It could also be cookie-related.  Try clearing RPoL cookies in your browser.

It is definitely not necessary for all recipients to read an rMail to clear the new rMail indicator on your account.

Clearing cookies and logging in didn't fix it. The rMail (and my previous ones) had the rolling stone instead of the meteor icon before I deleted it.

I very rarely get rMails, so I'll just check if the top right link is bold when not on the homepage, to see when new rMails have arrived.

I sent you an rmail.  Getting a new one will also usually fix this problem once you read it.

Yip, that fixed it. Many thanks.