Veselnitskaya is a paid member of a group registered to lobby against the Magnitsky act[1]. The group paying her was organized by a former GRU agent[2] and paid for by a Russian oligarch Denis Katsyv.
Reversing the Magnitsky act is pretty much the number one thing the Russian government would like.
Of course there is nothing wrong with this in itself. But while Veselnitskaya may not have been a Russian official, she was promoting official Russian policy and paid by politically connected Russian interests.
[1] https://en.wikipedia.org/wiki/Natalia_Veselnitskaya#Advocacy...
[2] https://www.grassley.senate.gov/sites/default/files/judiciar... (Note this complaint was made in 2016, before the election)