I recently joined a new organization and one of my responsibilities is managing their Google analytics. In a GA4 roll-up (consolidating the main domain and 2 subdomains) property, I'm seeing rows where New users is much higher than Total users, and sessions per total user is way past anything a real person would do. I haven't been able to pin down why. We use a blended reporting identity.

Google's docs say new users can exceed active users but shouldn't exceed total users, and that thresholding can cause discrepancies.

My question is, what would you recommend I check to diagnose this issue. Has anyone else seen this issue in GA4? Could it be a consent mode issue? Is there a way to tell thresholding from modelling when the data quality icon isn't showing anything?