This may help out. NJCAA (National Junior College Athletic Association) has different signing rules from the NCAA - I Googled the following:
https://njcaa.org › eligibility › faq
A student is allowed to sign a Letter of Intent with both a NJCAA and a NCAA college without sanction. ... If a student does sign with two NJCAA colleges, that student will become immediately ineligible to compete in NJCAA competition for the next academic year in any sport.