Hi,
This means that you've made a mistake in your settings.
For example, if you've selected the "confirmed" status in the "created" column of the menu System>Order statuses, it will directly create the order with the status "confirmed" instead of "created", like it is by default.
It could also happen with mass actions wrongly configured (menu System>Mass actions), or with custom plugins.
I actually don't think that it comes from the stripe plugin itself as I don't see any way it could confirm the order before the payment, reading its code.