Wow, that does sound like a major problem in the tax law to me.

Example: Take two people, "Bob" and "Joe," who have identical tax situations in 2019, allowing them the "sweet spot" of EIC. On New Year's Day 2020, Bob worked for 8 hours, but Joe did not, and then neither of them worked for the remainder of 2020. Bob gets $6k of EIC, and Joe gets didly squat? For 8 hours of work?

Dang, if I had a client like that, my ethics would be sorely tested on that one. "Are you SURE you didn't earn any income at all? Not even babysitting or something?"