Answered PM won't let me read most recent message

When I flip over the PM tab it shows the last reply was from the other participant some time last night. It says the same thing in the box at the bottom when I'm actually viewing the conversation. Here's the issue: it won't let me view the message that was sent, even after I've refreshed the page or gone to a different page and come back to it.

 

It finally loaded/let me see it.

 

Thank you, I will.