Hello Pro Team,
We recently ran into an issue where Pro will not add the full AGOL service to the map. We have an AGOL hosted feature service consisting of 4 tables:

When trying to add this service to ArcGIS Pro via the Add Data button, Pro only adds the top table in the service (Number "0" in the rest) and ignores the other tables in the service:

This appears to be a bug, since this should be adding the entire service to the project.
Please let me know if you need any additional details.
Thanks,
Amanda Huber