Today I was shooting across a ravine at some rocks I ranged at ~ 580 yards. I am using an NXS 5.5-22x56 with the NP-R1 reticle. As I looked through it at the target, the reticle would gradually fade away, out of focus. If I looked at something out of the scope then back through it, the reticle would appear again, nice and clear. I was also using a VX-III 6.5-20x50 LRT on another gun and didn't have the problem or at least it wasn't as pronounced. Both scopes were on max power. When I turned the NXS down to 12-14x, it was better. Low light conditions today with overcast skies. I've never experienced this before. Anyone know what's going on? Thanks.