I did a quick google search - sounds like this might be your situation.

Code L: Loans treated as deemed distributions under section

What is a Deemed Distribution? A deemed distribution occurs when the participant violates the terms of the 401k participant loan (e.g., loan amount, the loan term, and the repayment schedule). ... Lastly, a deemed distribution is not eligible for rollover to an IRA or another qualified plan such a a solo 401k plan