large "other" category in ipad storage

I have an iPad mini 2. Since the "other" category in the iPad storage seemed too high, I erased all data and setup the iPad again with my iCloud account. I have the latest iOS installed. However, I did not restore from any backups. So basically it was like a new iPad. But within 5 minutes almost 7 GB of the total 16 GB filled up with "other". Is this a bug?