I know the problem existed in the 60's.....but think that for the most part on the more modern, mid to higher priced scopes produced say from 1983 on.....the POI doesn't shift enough to be a factor for anything other than benchrest, or long range shooting.........but in my mind, the more moving parts the greater the odds of this type problem occurring.........I've come to the opinion that a fixed 4X is plenty on a big game rifle, and am slowly going to be replacing everything but Leupolds and Bushnell Elites with fixed powers.........I think a good heavy barrel varmit rifle can stand a higher powered scope for long shots on small critters.........From my experience at the range, my groups from a 4X are very close to the same as with the scope set to 12X or 16X ....at a hundred yards.............but believe the additional field of view from the lower powered scopes are more beneficial in the field...........where most of my shots are 100 yards or less........
I wouldn't bet on the lower end lines.............Seems most of the low end scopes start good but don't hold up for any length of time, at least they haven't for me..............Ain't gonna call no names......