Heya @cataclysm , we did ship a fix for this! Would you mind verifying if things are again working as you intended? You would have to redeploy your site (at some point, since a few days ago, when we quietly put the fix live for our non-enterprise CDN - Oct 14)
If not, I can tell you don’t want to share your sitename publicly based on your consistent use of example.com , but if you see it not working as intended, could you share the x-nf-request-id ([Support Guide] Netlify Support asked for the 'x-nf-request-id' header? What is it and how do I find it?) for a request that didn’t work? Nobody except our staff will be able to correlate that with a hostname 
PS: This test requested is “use with your existing configuration”, not “change your primary custom domain as you’ve said you don’t want to do”.
Thanks in advance for your help!