Yes, I did some testing and looks like IE11 has issues with fixed backgrounds. Specifying the background-attachment:scroll seemed to fix the issue for IE but breaks the parallax backgrounds in Chrome/Safari. Let me do some more testing and get back to you. I know this is taking time – but let’s hope we are getting closer to a solution although I think we may still have other issues to tackle in IE11 like this one –
If you do not have sizeable IE11 traffic, I wouldn’t worry too much about this. And chances of these users choosing a zoom of less than 100% (which is when the problem occurs) would be even lower. Hope you agree.