You've made sure that your Local Files are supported. You can find a list here.
Remove any offline devices listed here and then try a clean reinstall of the app on all your devices by following the steps here.
Try toggling off Hardware Acceleration (on the Desktop app, three dot menu > View > HardwareAcceleration).
Try adding your Local Files over a different network connection to see if the issue persists.
Your devices are all up to speed with any firmware or driver software updates. If you see any pending updates, make sure to install them, then try restarting your devices to see if that does the trick.
We'll be keeping an eye out for your replies, thanks!
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