Has anyone had trouble with the 5.5 x 22 NF holding POI ? I was shooting yesterday and had it happen twice at 600 yds , clicked up to 44 and shot ,7inches high 2 shots, 3rd one settled in, dialed up to 700 yd shot dead on, moved back to 600 yd same thing 6in high. Last week scope was fine at 44 clicks at 600 yds. I have had trouble in the past with scopes not holding POI, but not the Nightforce ..................................................... Shooting in 0 wind cond.