Hi Harry,
You are probably referring to the ICheck Radio Buttons widget (https://github.com/simo101/iCheck-Radio-Buttons), which is not fully functional anymore after upgrading to Mx 8.10.1.
Custom widgets can get broken after you upgrade the Mendix Studio version, so choose your widget extensions wisely and keep in mind that upgrading could be “blocked” due to widgets which are not supported (yet).
If you are able to fix the widget yourself, you could do a pull request to https://github.com/simo101/iCheck-Radio-Buttons
This widget is created by Simon Black, an active member of the Mendix Community; but he might not be available to help. As this widget ‘only’ has Community-Support, you can ask around (like you do) or maybe fix it yourself.
In the meantime: I recognize these kind of errors, you could try to put a container around the widget and make that conditional visible based on “$currentObject != empty”. At least the widget is then not loaded for empty objects. Does that help?
Kind regards,
Johan