What about it? The fact that it says January 2 while the caption says it's through January 7? I'm assuming that's just because the labels are generated at 11 day increments and Jan 7 isn't 11 days away from the 2nd.
Ah, that's definitely strange. A bug in the graphing software, maybe?
I think it's more likely that there were one or more manual steps in generating the graph, and someone just kept going with 2020 instead of typing 2021. The author should explain what went wrong there if this reaches their attention.
Or it's a typo, and who cares?
Maybe a date formatting problem? I saw something similar in the past due to passing the wrong format string, and Jan 2 was the Saturday of the "last week" of 2020, before the "first week" of 2021?