Unhappy marksman - Burris XTR II 8-40x 50mm Rifle Scope 34mm Tube Second Focal Plane SFP

I purchased one of the 8-40 Burris scopes last year. It works great. BUT I just purchased a new one to use in small bore matches at max distance of 50 yards. The new scope would not focus/ clear up at 50 yds. I had to decrease the power setting to 18x. Which makes it useless to me. My other one is crystal clear on 40x. So needless to say this one will get returned. Maybe I simply got a bad one. It happens.