I sent a mass PM to the users registered on my test board, and it decided it was going to send them like tons of copys of the same message over and over again.
Send a mass mail to all registered users (PM not email!). Wait a few seconds, PM comes once. Then wait a few more minutes, and you start getting more.
I tried it and it again and it did it again. I stop it by deleting the message in the queue (stays on 0% the entire time)
I can't reproduce it. Can you post exactly what mass mail settings you're using? Did you schedule it for immediate delivery or later date?
Also, what beta version are you using?
Thank you for your bug report.
This bug has been fixed in our internal code repository. Please note that the problem will not be fixed here until these forums are updated.