Hi @sallewar,
According to official documentation Page diff functionality is not supporting SPA, but also some dynamic components that heavily use JS or retrieving data/content via Ajax calls.
It is not possible to enable Page diff to be supported in SPA, due to the way how Page diff functionality has been deigned. I do not think there is any simple workaround, probably the only way will be to customize Page diff functionality, which in general could be difficult and is not recommended, as most likely will require customization of some core mechanism.