I’m off for the night. I’ll grab a PC and take a look tomorrow.
Please, let me know which version of IE you’re testing on.
Additionally, in IE, press F12 to open the developer console. Somewhere in there is a setting that controls the rendering engine. I forget the label but you should see it. It might be called Compatibility Mode? Essentially, you can set a new version of IE to render as any of the past versions. Please, make sure your new version of IE isn’t set to render as IE 10 or 9 or similar old version. That’s something I’ve seen happen in the past so sharing in case it’s the case here.