unwanted phrase in subject line when emailing members

We have been using the "members-1813882@toastmastersclubs.org" email now and again to send emails to all members.
Since early February these emails all now arrive in our inbox with the subject line including an extra phrase [Next meeting theme] at the beginning, and it isn't usually about the next meeting theme!
Can we get rid of this unwanted phrase?

1) How are you sending these emails, Your email client, the agenda application, the basic email application?
2) The subject will be in front of them before they send the email, they should change it.
3) The person who is sending the emails needs to clear their browser cache, and try again.

Thanks for your reply Brian,
I can't speak for all the exec, but I personally just use that email address from my personal Outlook email application, not from my browser or the club website.
The subject line does not have this phrase in when I send it (I checked in my sent box just now to confirm that) but it does when it is received by the members.

see support.toastmastersclubs.org/doc/item/email-and-contact-forms

Subject prefix
You can add a prefix so as to make emails from your club more distinctive. This can be especially useful if members belong to more than one club which uses FreeToastHost.

Enter the new prefix and save.

For example, entering ABC TM will cause every email subject line to start with [ABC TM]

thanks Steve, I found that the unwanted phrase was already in as a prefix, and was able to delete that. Hopefully this will fix our issue.