[Benjamin]

Based on the information you’ve described, the issue might be related to the way you’re querying your custom dimension. In Google Analytics 4, custom dimensions sometimes require a specific syntax and you may need to reference them in a different way than just 'customUser:dimension1'. Instead of applying the WHERE clause to Dimensions directly, you need to use the dimension name more specifically. For example, if the dimension is a custom User scoped dimension, you might need to use something like User_Dimensions.<Your_Custom_Dimension_Name>. Additionally, ensure that your data type format and date are correct. If these suggestions do not solve the problem, it would be beneficial to check Google’s documentation on querying custom dimensions in GA4, as they have detailed instructions and guides which can help resolve your issue.

[Benjamin]

You can certainly keep your old Universal Analytics property while starting to use your new Google Analytics 4 (GA4) property, to ensure that all tracking is ongoing while you adjust to the new system. It won’t affect your GA4 data. Whether to keep the old UA tracking code or not, it completely depends on your requirements. Regarding the old events, GA4 will not automatically transfer them. GA4 works with a different event model than UA, and you’ll need to set them up manually in GA4 once again. Old ‘ga(‘send’) events can’t be directly transferred. The GA4 event model is more flexible and allows for more customization so you might consider mapping out how you want to track events in GA4, and implement those changes gradually. Also, though your existing UA property won’t stop working after July 1st, Google will stop creating new properties in UA, hence building comfort with GA4 will be useful for future analysis.

[Benjamin]

The incompatibility issue you’re encountering stems from the fact that “pagePathPlusQueryString” and “sessionCampaignName” dimensions belong to different scopes in Google Analytics 4. The “pagePathPlusQueryString” is in the ‘Page’ scope, while “sessionCampaignName” is within the ‘Session’ scope. These scopes are mutually incompatible— you cannot combine them in a single report. Data in GA4 is processed differently based on its scope.

For a solution, consider separating your reports based on the scope: one with ‘Session’ scope, featuring the “date” and “sessionCampaignName” dimensions, and another with ‘Page’ scope, combining the “date” and “pagePathPlusQueryString”. You can then splice and dice the data from the two separate reports to get the information you need. Alternatively, it may be possible to use other compatible dimensions that serve a similar purpose in your use case.

Always remember to ensure that the dimensions in your report are all compatible (within the same scope) to avoid errors. This is key when working with Google Analytics 4’s API.