One of the other developments in the advance of Tilt-Rotor technology is in wing sweep. The wings on previous Tilt-Rotor designs have had the wings have some forward sweep out of concern for possibility of potential impact of the proprotors with the leading edge of the wing in forward flight. The V-280's wing doesn't.
Believe it or not, the straight wing was implemented almost entirely for cost reasons. The manufacturing methodology used with thick carbon skins, large cell carbon core, and paste bonds plus the tooling for a linear structure is drastically cheaper to build than the V-22 or 609 wing design.
The forward sweep on other tilt rotor designs is partially for flapping clearance, partially for aeroelastic stability/wing bending modes, but also CG/AC balancing since the nacelle pivots the rotor and engine masses as a single large unit.
Airplane mode flapping on V-280, particularly with the increased physical flapping capability, was kept in check by advanced flapping controller logic to bias more authority at the critical wing azimuths. In the end I don't think that was ever actually needed.