Hi again Eric,
If it’s running well with twentysixteen, then I’m afraid it’s a theme issue. So you might want to contact Elegant Themes’ support to notify them of this issue happening in Chrome.
I did a bit more testing on your site. That rendering issue happens – for me – when the top header shrinks to smaller size. Once that’s over, the rendering seems fine. I tried some css fixes, but it doesn’t really help.
At the moment I have little else beyond what I have already provided. Let me know if you have any follow up questions.
Cheers,
Andras