EditForm causing RenderTreeDiffBuilder error in blazor

I have a blazor component which has an EditForm component, but its causing an error in the RednerTreeDiffBuilder which is strange as Ive used this many times and never had this issue.

<EditForm EditContext="FormEditContext" Context="form" OnValidSubmit="SaveChanges"><!-- Form Code Here --></EditForm>

The error is on line 701 because the componentState is null.

var componentState = oldFrame.ComponentStateField;// Preserve the actual componentInstancenewFrame.ComponentStateField = componentState;newFrame.ComponentIdField = componentState.ComponentId;

Hopefully someone has experienced this and knows the solution!