Google Play Install Referrer is Oddly Inconsistent

Question

Recently I've been attempting to attribute Android app installs to specific Google Ads Campaigns. To do this, I began by tagging all my Google Ads campaigns with data about the campaign and later retrieving the installReferrer string.

I run the following campaign types: Display and App
All campaigns have a referrer parameter that gets inserted into url at click time, containing a url-encoded JSON string of the campaign's metadata (name, id, etc.).

Once I pull this data from thousands of devices, I come across several inconsistencies.

1. sometimes the referrer string contains a query string: gclid=SOME_GCLID_HERE.
2. sometimes the gclid is not encoded, and sometimes it is: gclid%3DSOME_GCLID_HERE.
3. sometimes the referrer string contains source and medium attributes only: utm_source=google-play&utm_medium=organic
4. sometimes there is just no referrer string at all
5. sometimes I get the actual referrer string I expected

I can't seem to find documentation on these fluctuations in behavior. What could explain all of this?

Is there any resource I can use to figure why the GCLID comes with some, but my expected string comes with others?

Also, why are some GCLIDs URL encoded and some are not?