Can someone explain how the ADP ACP nondiscrimination test applies when my employer does not contribute anything to the 401K. It's only employee contribution.

I was informed my 2022 contributions would be returned due to failed audit.  I researched and understand the HCE NHCE scenario and why the audit exists but if the employer does not contribute anything how is the NHCE disadvantaged?  I don't think this audit should apply to this situation.  Any insight appreciated, thanks in advance.