We're experiencing the same issue on both iOS and Android, namely that on app launch we use the exact code documented here to register push token: https://experienceleague.adobe.com/docs/campaign-standard/using/administrating/configuring-mobile/su...

The issue is that we can see the token is available in the app through debugging, and we can even use collectPII to send that token to a test field in ACS and this works fine, however the setPushIdentifier function doesn't populate the field in the Registration Token in Adobe Campaign Standard.

If we kill the application and relaunch it then the registration token is correctly sent.

It appears that there is some delay in the SDK registering the token and making available for all SDK functions.