Retirement tax questions

Hi, I have a similar situation but with twist.  I have a loan from my Vanguard 401-k and I've been laid off. Vanguard says my company set it up such that these loans have to be paid back WITHIN 90 DAYS of layoff. But the Tax Cuts and Jobs Act says the deadline is now the due date of the employee’s tax return for the year in which the distribution occurs, including extensions. I need to know which one is the OVERRIDING RULE. Thank you.