pretty much misclassification, is my understanding.

the fact that someone else was in the exact role classified as a W-2 wage employee should seemingly make it a slam dunk, if you can get copies of the job description and any payroll paperwork, i should think that's a smoking gun because it shows they know the law and are willfully breaking it. a lot of small business tyrants pull the "i forgot to carry the one" when caught redhanded.

anecdotally, the amount of 1099s in the US that should actually be W-2s must be mind boggling. the only people i have ever known not to have experienced it directly are like fast-track to PMC academics and foreign service weirdos that have only worked government jobs.