Did some quick testing on this. Set up a 120 planet realistic map, no factions, no plots, no waves, 2 diff 7 vanilla AI's. While still on .053, I ran a cap of mark III's down each of five separate paths on the map to see how far they'd get, ran caps of mark II's and I's down a few of those same paths, made notes, then patched to .054 and precisely repeated the operation. Number of stars successfully scouted in .053 are before the slash, in .054 are after the slash:
Path 1 - III's 9/7, II's 4/4, I's 3/3
Path 2 - III's 6/6, II's 4/4, I's 2/2
Path 3 - III's 8/7, II's 4/4, I's 3/3
Path 4 - III's 10/7
Path 5 - III's 10/8
Averages - III's 8.6/7, II's 4/4, I's 2.7/2.7
So from patch 4.053 to patch 4.054, I show roughly a 19% drop in scouting efficiency for Mark III's, and no discernible effect on the other two marks of scout.