You can fix this problem. Unfortunately, the tool you need is your wallet. Sad to say the moderately priced scopes with parallax adjustments sometimes have a setting where sharp focus and minimum parallax aren't quite the same. In other words, you can choose one or the other, but not both at the same time. Generally speaking, I dial out the parallax and just live with the blur.

My scopes costing $1500 or more tend to be sharp when parallax is at a minimum. The less expensive ones......... not so much.