This inconsistency typically stems from integration settings between GA4, Google Merchant Center (GMC), and Google Ads. Please try the following steps:

GA4 Admin > Property Settings > Product Links > Merchant Center

1. Verify linking status is active
2. Ensure data sharing settings are enabled
3. Confirm the same GMC account is linked across properties then

Verify Google Ads Configuration

1. Enable auto-tagging
2. Check Enhanced E-commerce settings
3. Verify conversion tracking setup then

Review Data Stream Settings

1. Enable enhanced measurement
2. Check e-commerce data collection settings
3. Verify product data collection is active

That's what I can think of at the moment, please follow up if you have other issues