It seems like your custom dimension “Is site” might not be correctly set up, since it’s affecting your “Engagement rate” and “Bounce rate” measurements. This could be due to a variety of reasons, sometimes the custom parameters aren’t defined correctly in the code or the values being passed for that dimension aren’t recognized. Instead of being associated with each user’s behavior, it seems the custom dimension is acting like an event and hence not capturing engagement correctly. You might have to revisit the custom dimension setup to make sure it’s collecting and analyzing the data as expected. Additionally, check your settings for “Engagement rate” and “Bounce Rate”, as there may be conflicts with how the custom dimension is defined. If the problem persists, you might want to reach out to Google Analytics support for a pointed resolution to the issue.