liftingcortical

Seems like it no longer sends the Content-Type header properly:
HTTP/1.1 200 OK
Date: Thu, 08 Nov 2018 09:04:28 GMT
Server: Apache
Vary: Accept-Encoding,User-Agent
Last-Modified: Wed, 07 Nov 2018 11:54:28 GMT
Accept-Ranges: bytes
Content-Encoding: gzip
Strict-Transport-Security: max-age=31536000
Referrer-Policy: origin
Link: </wp-content/cache/minify/469a8.js>; rel=preload; as=script
Link: </wp-content/cache/minify/5a084.js>; rel=preload; as=script
Link: </wp-content/cache/minify/545b0.js>; rel=preload; as=script
Link: </wp-content/cache/minify/5d1ad.js>; rel=preload; as=script
Link: </wp-content/cache/minify/6aaea.js>; rel=preload; as=script
Link: </wp-content/cache/minify/99006.js>; rel=preload; as=script
Link: </wp-content/cache/minify/02155.js>; rel=preload; as=script
Link: </wp-content/cache/minify/6e269.js>; rel=preload; as=script
Link: </wp-content/cache/minify/3ee41.js>; rel=preload; as=script
Link: </wp-content/cache/minify/0b066.js>; rel=preload; as=script
Link: </wp-content/cache/minify/1ebad.js>; rel=preload; as=script
Link: </wp-content/cache/minify/0c65a.js>; rel=preload; as=script
Link: </wp-content/cache/minify/344a7.js>; rel=preload; as=script
Link: </wp-content/cache/minify/4e8c0.js>; rel=preload; as=script
Link: </wp-content/cache/minify/c8498.js>; rel=preload; as=script
Link: </wp-content/cache/minify/4fb56.js>; rel=preload; as=script
Link: </wp-content/cache/minify/6cca5.js>; rel=preload; as=script
Link: </wp-content/cache/minify/7766c.js>; rel=preload; as=script
Link: </wp-content/cache/minify/4dd78.js>; rel=preload; as=script
Link: </wp-content/cache/minify/5c1bc.js>; rel=preload; as=script
Link: </wp-content/cache/minify/0351e.js>; rel=preload; as=script
Link: </wp-content/cache/minify/3ec36.js>; rel=preload; as=script
Link: </wp-content/cache/minify/32d0a.js>; rel=preload; as=script
Link: </wp-content/cache/minify/5f0d1.js>; rel=preload; as=script
Link: </wp-content/cache/minify/31e22.js>; rel=preload; as=script
Link: </wp-content/cache/minify/59632.js>; rel=preload; as=script
Link: </wp-content/cache/minify/d6903.js>; rel=preload; as=script
Link: </wp-content/cache/minify/9a50d.js>; rel=preload; as=script
Link: </wp-content/cache/minify/b9b52.js>; rel=preload; as=script
Link: </wp-content/cache/minify/275d1.js>; rel=preload; as=script
Link: </wp-content/cache/minify/67b50.js>; rel=preload; as=script
Link: </wp-content/cache/minify/822e0.js>; rel=preload; as=script
Link: </wp-content/cache/minify/98589.js>; rel=preload; as=script
Link: </wp-content/cache/minify/1e264.css>; rel=preload; as=style
Content-Length: 12628
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive

Versus a proper response after purging all caches (see last lines)
HTTP/1.1 200 OK
Date: Thu, 08 Nov 2018 09:21:24 GMT
Server: Apache
Vary: Accept-Encoding,User-Agent
Last-Modified: Thu, 08 Nov 2018 09:09:06 GMT
Accept-Ranges: bytes
Content-Length: 12582
Strict-Transport-Security: max-age=31536000
Referrer-Policy: origin
Link: </wp-content/cache/minify/469a8.js>; rel=preload; as=script
Link: </wp-content/cache/minify/5a084.js>; rel=preload; as=script
Link: </wp-content/cache/minify/545b0.js>; rel=preload; as=script
Link: </wp-content/cache/minify/5d1ad.js>; rel=preload; as=script
Link: </wp-content/cache/minify/6aaea.js>; rel=preload; as=script
Link: </wp-content/cache/minify/99006.js>; rel=preload; as=script
Link: </wp-content/cache/minify/02155.js>; rel=preload; as=script
Link: </wp-content/cache/minify/6e269.js>; rel=preload; as=script
Link: </wp-content/cache/minify/3ee41.js>; rel=preload; as=script
Link: </wp-content/cache/minify/0b066.js>; rel=preload; as=script
Link: </wp-content/cache/minify/1ebad.js>; rel=preload; as=script
Link: </wp-content/cache/minify/0c65a.js>; rel=preload; as=script
Link: </wp-content/cache/minify/344a7.js>; rel=preload; as=script
Link: </wp-content/cache/minify/4e8c0.js>; rel=preload; as=script
Link: </wp-content/cache/minify/c8498.js>; rel=preload; as=script
Link: </wp-content/cache/minify/4fb56.js>; rel=preload; as=script
Link: </wp-content/cache/minify/6cca5.js>; rel=preload; as=script
Link: </wp-content/cache/minify/7766c.js>; rel=preload; as=script
Link: </wp-content/cache/minify/4dd78.js>; rel=preload; as=script
Link: </wp-content/cache/minify/5c1bc.js>; rel=preload; as=script
Link: </wp-content/cache/minify/0351e.js>; rel=preload; as=script
Link: </wp-content/cache/minify/3ec36.js>; rel=preload; as=script
Link: </wp-content/cache/minify/32d0a.js>; rel=preload; as=script
Link: </wp-content/cache/minify/5f0d1.js>; rel=preload; as=script
Link: </wp-content/cache/minify/31e22.js>; rel=preload; as=script
Link: </wp-content/cache/minify/59632.js>; rel=preload; as=script
Link: </wp-content/cache/minify/d6903.js>; rel=preload; as=script
Link: </wp-content/cache/minify/9a50d.js>; rel=preload; as=script
Link: </wp-content/cache/minify/b9b52.js>; rel=preload; as=script
Link: </wp-content/cache/minify/275d1.js>; rel=preload; as=script
Link: </wp-content/cache/minify/67b50.js>; rel=preload; as=script
Link: </wp-content/cache/minify/822e0.js>; rel=preload; as=script
Link: </wp-content/cache/minify/98589.js>; rel=preload; as=script
Link: </wp-content/cache/minify/1e264.css>; rel=preload; as=style
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html; charset=UTF-8
Content-Encoding: gzip

So, yes, purging caches fixed. I’m guessing temporarily.
Cheers!