Thank you – that suggestion to run Jekyll in verbose mode is really helpful, helped me zero in on the file that was causing the problem. That should be in your docs, maybe it is and I missed it. Again, really appreciate that.
Here was the culprit, a blog post containing the following. Removing the “created_at” line fixes the build on Netlify.
(To answer your question, I’ve never had a problem on my local machine or even on Netlify until I posted this question, and nothing has changed in this file in about two years. Usually takes about a minute to build. And attempting to re-deploy previously successful builds failed as well.)
{% highlight json linenos %}
...
{"created_at":"Thu Dec 01 09:54:56 +0000 2016","id":804262498022981632,"id_str":"804262498022981632","text":"\u4e09\u6bdb\u3060\u304b\u3089\u3001\u3063\u3066\u3053\u3068\u3082\u306a\u3044\u3051\u308c\u3069\u3001\n\u30aa\u30c3\u30c9\u30a2\u30a4\u306e\u3088\u3046\u306b\u898b\u3048\u308b\u3093\u3060\u3088\u306a\u3041\u3001\n\n\u3053\u306e\u30b3 https:\/\/t.co\/yfl9SpTVCS",...,*"lang":"ja"*,...}
{% endhighlight %}
Successful deploy: https://app.netlify.com/sites/prod-www-dremio/deploys/5d4e5fcd0406800009a64805