By now, you might know about Twitter's hidden reply function. It basically gives users the opportunity to "hide" a reply so it doesn't appear below their tweet, though it can be viewed in a separate area.
These tweets can still be seen by other Twitter users if they choose to see hidden replies.
And last week, MTV tweeted in celebration of Rihanna's album Anti turning 4 which, naturally, got a lot of engagement. They also tagged Rihanna's Twitter handle in the tweet.
But then people started noticing that MTV had hidden a reply to the tweet. The hidden tweet was from Twitter user @Freebird8626 sharing her crowdfunding page, asking Rihannas to help raise awareness of their cause.
Speaking to BuzzFeed News the 33-year-old woodworker, who asked not to be named, said that she didn't know her reply had been hidden by MTV until other Twitter users notified her.
@Freebird8626 said she has a rare neurological condition called complex regional pain syndrome, or CRPS. She said she got it after an injury at work a year ago.
People were angry the tweet was hidden saying it was "horrible" to do that to "someone who is in need".
And they wondered if MTV was aware that their hidden replies were still able to be seen.
Other people who have been diagnosed with CRPS started replying to the tweet in solidarity.
Since the issue was raised online, she said people have been donating money anyway, and that she's grateful for all the support.
MTV has not responded to our requests for comment.