Thank you Jay, very pleased to understand what has caused the issue, but I have been unable to Roll Back to the previous version. I downloaded version 2.2447.5.0, from https://whatsapp-desktop.en.uptodown.com/windows but unable to install this version as WhatsApp says this version now expired and forces you to the latest version. I think we may have to wait until WhatsApp release a fix!
Unless someone comes up with a solution?