Rise Storyline Block bug in IE

A client informed me of a problem in a Rise course that we are making. They said that a grey bar would appear when trying to scroll past a Storyline interaction. 

It turns out that they are using Internet Explorer and I was able to replicate the bug myself.

Please take a look at this unbranded course in IE to see for yourself. Your cursor needs to be over the interaction and you need to use your mouse scroll wheel to scroll down. 

https://rise.articulate.com/share/iTmUaaZO0BQY1xWNNFIECPAG77IliCvc

Strangely, it doesn't on all Storyline blocks. I think it may have something to do with the proximity to the bottom of the page.