It is not a new issue and I have encountered it before but never thought anything of it.
Other browsers – Yes same response
Other themes – Yes same response
Waiting to see if it clears, as noted earlier – It does not clear itself. What I have found is that if I press enter on the URL it redisplays the page including the message
As this function is not a normal user function I will just have to press enter in the URL. This is happens when sending an email from pending changes screen and the User Online widget. This does not happen when I send a message from the users screen