A bug report with steps to reproduce (even a link to the specific GitHub page involved would help) would be really useful if you are still seeing this. Please cc "bzbarsky". Also worth checking whether the problem persists with extensions disabled, if it's reproducible enough to do that with...
Yes, that one is on my to-investigate list already. Thank you for the reminder!
Chrome has started just blocking the HTML parser completely on stylesheets. That means it doesn't end up with FOUC (except insofar as there is renderable content before a sheet that is affected by the sheet), but at the cost of less parallelism and slower pageload...
A bug report with steps to reproduce (even a link to the specific GitHub page involved would help) would be really useful if you are still seeing this. Please cc "bzbarsky". Also worth checking whether the problem persists with extensions disabled, if it's reproducible enough to do that with...