The Minnesota Independent asks the question.
I pointed the reporter to 11 C.F.R. section 11 110.3(d):

(d) Transfers from nonfederal to federal campaigns. Transfers of funds or assets from a candidate’s campaign committee or account for a nonfederal election to his or her principal campaign committee or other
authorized committee for a federal election are prohibited. However, at the option of the nonfederal committee, the nonfederal committee may refund contributions, and may coordinate arrangements with the candidate’s principal campaign committee or other authorized committee for a solicitation by such committee(s) to the same contributors. The full cost of this solicitation shall be paid by the Federal committee.