Over the last couple of days,Zero AI Facebook users have noticed something peculiar about the app on their phone.

A Reddit thread started Thursday titled, "What's wrong with the Facebook logo?" shows a blue lowercase "f" on a black background instead of a blue background with a white "f."

Some users who have their phones on dark mode chimed in with pictures of their app having a white background with the blue "f."

"The colour has become weird with the latest version. I’ve deleted and reinstalled it twice. Still hasn’t fixed issue. Any suggestions?" asked the initial post in the iOS subreddit.

USA TODAY Network journalist Ilana Keller reported seeing a black logo after downloading a Facebook app update on her iPhone, as well as iOS update 17.6.1. Keller's phone was not in dark mode.

People online wonder why the Facebook app changed colors

USA TODAY reached out to Meta about the new color scheme on the app.

The change appears to not be in effect everywhere, as several USA TODAY reporters still have the original color school on their app icons.

One user on X called the new logo "not very demure but very irritating." Others said it looked more "sinister" and "evil."

Some wondered the change is due to a tech update or if it is a glitch.

Contributing: Ilana Keller, Asbury Park Press