The standard salesforce header…  A wild and dangerous place…  It looks like there is an extra image being posted there.  But I’m not sure there is going to be anything Skuid can do about that.  We call the header,  but don’t change it… 

But here are a few thoughts. 
1. Does this happen when you preview the page from within Skuid.  Or only when you use your override.   IF the latter - you might check your VF override page code. 
2. Try to turn off the header in the page builder (its in the page properties at that top of the page) and then turn it back on. 

If these things don’t work - I think you should log a case with Salesforce.  

Thanks for the quick response.  To answer your questions.

1.  It happens both from within the Preview and on the override
2.  Toggling the header doesn’t seem to have an effect

This only occurs in Chrome, not IE.