Maybe the reason these people are reporting not being paid is because they have not submitted their W-9. I just got a e-mail asking to submit mine and in the e-mail it clearly says

"For compliance reasons, we're required to have a completed W-9 form from you on file so we can process a 1099 tax form at the end of the year and provide you with a copy for your own tax reporting. The 1099 form will indicate your total income from Shutterstock for the year and is also filed with the IRS. For this reason, we cannot process any payments to you until we have your completed W-9 on file."

So that could be the reason for the rumor starting over in the Shutterstock forum...

It could also be they didn't reach minimum payout.

Just My Opinion ...