If I understand your situation this is working as designed.
In your first situation the volume size is 1GB and the quota size is in excess of this, specifically 2GB. In Windows explorer you cannot see more than what the volume is currently sized to.
Quotas are used to restrict what Windows explorer can see. If the volume was sized to 2GB and the quota set to 1GB, then you would only see 1GB in Windows explorer.
The volume will only resize when the nearly full threshold is met, by default this is limited to only 120% of the original size. Also, new in ONTAP 9 is that the incremental size is not set but rather will automatically increase in size depend upon how the volume is being used.
If I've misunderstood the issue then please advise.