Hi Sean, thanks for looking into this.
When exporting without a stroke it is extremely quick on my system as well, so I don't get the progress bar. The pixel layer is not strictly related to the error, but I added it in order to trigger the progress bar – it shows up when I export with both the "mainland" (no stroke) and pixel layer visible.
However, when I add the stroke to the mainland layer I don't get the progress bar, even with the pixel layer, and everything hangs. Also, it seems that it is just the current file that freezes, and I can still close the file (I even get the prompt to save it) and carry on as usual.
I've attached my export settings. I think it's just the default PDF for print. (Not shown is embedding "all fonts", as well as "subset fonts" and "allow advanced features" checked")