Hey glynnebl,
Welcome to Apple Support Communities.
To start, we recommend trying a different color to see if it happens on all of them. Afterwards, restart the Mac. Restarting has been known to resolve software related issues. To restart, choose Apple Menu > Restart.
If the issue still happens, make sure your macOS is up-to-date. The latest macOS version is 13.5.1. To check for updates, follow the steps below or in this article: Update macOS on Mac.
To check for new software, open Software Update. It's in System Settings (or System Preferences), which you can open from the Apple menu in the corner of your screen:
* Choose Apple menu > System Settings. Click General on the left side of the System Settings window, then click Software Update on the right.
* Or choose Apple menu > System Preferences, then click Software Update.
If Software Update finds new software, click the button to install it. You will be asked to enter your administrator password. During installation, your Mac might show a progress bar or blank screen several times, and you should avoid putting it to sleep or closing its lid.
If Software Update says that your Mac is up to date, then no new software is currently available for your Mac model. Software Update shows only software that is compatible with your Mac.
Hope this helps. Take care.