This is happening since last insider update and I think it's not strictly related to whatsapp.
It would have saved everyone a lot of time if you had made it clear from the start that you are running an Insider Build. It is perfectly normal for Insider Builds to show all kinds of bugs, which is the whole point of the Insider program - along with collecting this feedback through the correct dedicated channels for that, which is why there is a dedicated Insider Program section within this community along with the Feedback Hub on your phone. Posting your Insider problems in the board dealing with Production releases is a waste of your time and of everyone trying to assist you. Next time please post in the correct forum section.