QRP invest in LLC

From TaxAlmanac

I have been looking for answers for about a month and I don't see why this will not work. A client formed a C-Corp (holding company) which sponsored a Qualified Retirement Plan. client then rolls over their 401K into this holding company. The holding company then invests in the clients LLC as a more than 80% owner. The question is whether this arrangement will prevent the usual partnership relationships. I looked into related parties but I did not see anything about investments in a related party only loans to related parties. Please let me know if more info is needed. thanks!!