I was using the components before without two way binding since some of the fields I was displaying were nullable so I used ? in the Value="@(data?.allows?.Value)" but using @bind-value="data.not.allowed) must have left had assignment. Ok. Is there anyway around this because without the ? an error is produced when that field is displayed.
Instead two-way binding you can use Value and Change event to set the changes value.
Just a note, it should be @bind-Value not @bind-value.
Thank you I was able to use an inline Change to set the value.
I also moved this to the back end by adding a partial class for the EF class which was missing values and set the defaults for the nullable values as suggested in EF 8 best practice. This fixed the issue and no longer required the the change event handler for my needs.