What Broz said...
What you saw is not unexpected, at least by me, when shooting across multiple canyons/large swales or to the other mountain when shooting over a small ridge on the far mountain.
I've busted my butt setting up wind flags in a particularly tough 1400 yard spot. One day to set the flags. Wouldn't ya know? the next day no wind. No flyers!!
Next day, steady wind, flags were so damn confusing they did me no good.
However, could still hold Minute of Elk.