Flank marches colliding with forced evaders.

[gaesati]

Flank marchers must make a full on table move perpendicular to the table edge. Troops within 6" of the table edge must evade away from the edge.
Unit Enemy was within 1" of the table edge when the flank march arrived. Sadly, its evade only took it 2" further from the table edge. The flank marchers move on table but can only travel 4" when they collide with the rear of the evaders. Is this a legal move as the flank marchers move less than their full move? Is it a legal contact( seems not because it occurs in the manoeuvre phase)? Does the flank marcher stop moving the proverbial gnat's todger away?