I disagree. No self-respecting data person would do that without an explanation. I saw none at the CDC site.
In addition, who is getting more than two shots and why?
There is going to be some error rate in reporting, as long as people are involved.
So many people are involved, we are going to have some new people just learning the system, some old people forgetting things, some people with alcohol or drugs in them, some tired and overworked people, etc..
Rather than people getting a third shot, I suspect that the difference between doses administered, and the total of first and second doses, might be largely from those reports where they failed to specify which it was (a first or second). We see that when they break out how many of each vaccine was used: Pfizer, Moderna, Not Specified.