I have found a bug that appears to be reciprocated by a few other users, I have a screenshot of the console data below but have not actually attempted to find the root cause of the bug. As seen in the attached image, the html for each puzzle element has an issue where instead of only having a checkmark, it also includes an undefined value turned into textContent:
drive.google.com/file/d/1thgaIgI5CbFq50SJD_0KlJmsRgfZPr8o/view?usp=sharing
drive.google.com/file/d/1thgaIgI5CbFq50SJD_0KlJmsRgfZPr8o/view?usp=sharing