Opening threads in new tabs causing pop-up to view as text

[RiderXero]

Over the last couple days, on occasion, when I right click a thread and select to open in a new tab, I get a pop-up box like I'm trying to download the thread and it asks me to open as a text file. Sometimes it happens when I just click a thread to open it as well. It doesn't happen every time, but I just thought I'd point it out to see if it's something anyone else is experiencing or if a setting got changed without me knowing causing this to happen. Here's a screen cap:



This was right after I clicked the '72' to go to page 72 of the thread.