Been getting a glitchy inbox as well today at clraik, but I wasn't sure if it was because I was replying with Tapatalk or what, so probably now that I read you and knowing I'm not the only one, it must be a problem of the site
I'm having some private message glitching too. It'll keep showing me a new notification, but clicking on the link takes me to an old message, while the notification still stays lit that I have another new message. I eventually had to physically delete messages so it would stop saying they were new and alerting me about them.