In one of my posts here I had a referral link for Google Adsense. Recently, Google sent an email around that it will stop using them. I read that with half a mind and dismissed it.
However, this has one interesting consequence in WordPress - this link confuses
the_content() API call and it returns empty string. I removed this Adsense link (broken into several lines for clarity):
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and things were back in normal. No idea what is exact problem, just posting for the sake of others having the same problem. Thank you goes to commenter David that alerted me to this.