Currently the Badge Counter is not synced across different installations. e.g. if new messages are pusehd, then the Badge Indicator will update.
But when I read messages on a different device (e.g. PC, Tablet, Mobile), then the Badge will not get updated on other iOS Devices unless I open the Webex App on that Device.
I think this is not a good implementation for an Enterprise Application.
Other tools like Whatsapp, Signal or even MS Teams do not have this restriction.