Ah, OK, I see what's happening. Your IE 11 is set to Compatibility Mode for this app. This mode mimics IE 7, which Story Maps doesn't support.
You should be seeing a "Sorry! This story is not supported in Internet Explorer before version 11" warning message, but it looks like the way we chose to display that doesn't work in Compatibility Mode. We will fix that warning display on our end, but in the meantime, could you turn off Compatibility Mode? I think it's under Tools > Compatibility View settings.
I'm honestly surprised this was working until recently, as the code for this hasn't changed in about a year. Maybe your IE's settings have changed recently? Or you were using a different computer with different Compatibility View settings?
Alison