Purple FaceTime screen sharing icon appears randomly when i’m on normal calls

Hi The_beatles,

To rule out possible software issues, make sure you're using iOS 15.5. If you need to update, be sure to back up first as well: Update your iPhone, iPad, or iPod touch - Apple Support

"Update your iPhone, iPad, or iPod touch wirelessly

1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see two software update options available, choose the one that you want to install.
5. 
6. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do."

If that doesn't help, we recommend contacting Apple directly with this link: Apple Support

Best wishes.

Hello The_beatles,

Thanks for using the Apple Support Communities.

It sounds like you’re looking for help with turning off the screen sharing feature over FaceTime.

Is that correct? If so, you’re in the right place to receive support.

When you get a free moment, please try the steps in the link below in the section titled “End a screen sharing session.”

Share your screen in FaceTime on your iPhone or iPad - Apple Support

Giving the above steps a try can potentially resolve your issue. If you’re still experiencing the same problem after completing the steps above, please do not hesitate to reach out with some specifics on what you see for more help.

Cheers!