MBN nope, not on Windows 10 64 with IE, Edge or Firefox just open and close while REAPER is playing. ("blank" FlashFree pages btw)
And not only that, I tried pushing my luck with opening stuff and, Moving the window/s, that could usually make choppy audio but nooOOoo.. what the heck..
And I am using Asio4All if that helps with the investigation.
Edit: and ah yes, no classic themeing going on either, just default, I recall having an issue with a plug-in sometime, had to mention it, it's my duty.
Hope you sort it out.