session.clearStorageData() does not empty partition cleanly

Hope someone can help me out. I am trying to access a website which has a policy to restrict visitor from accessing too frequently between 2 access.

I am pretty sure that they are not achieving this by recognizing IP address. That means they are using client-side cookies, localStorage, etc. However, when I try to access it 2 times continuously. I got recognized. If I try to perform session.fromPartition('some_partition').clearStorageData(), I STILL GET RECOGNIZED!!! but if I try to do it with session.fromPartition('some_partition').destroy(), I can pass it through again.

Anyone can give me idea / direction to figure out what is happening? How can I solve it? Is it a bug of session module? Does the session partition not cleared cleanly? Any help would be appreciate. Thank you


UPDATE 1:

Seems that it is cause by a test of window.openDatabase(). I sure that I have run clearStorageData() of specific partition. How come the database is still remaining in that session?