Unreliable wheel part's GroundContact value
Wheels in 1.10 appear to require more force to register ground contact than in 1.9.1. Resting on the surface is not enough to set Part.GroundContact (https://kerbalspaceprogram.com/api/class_part.html#aa9eeb5535b88befd304c641da3e42b55) to true while ModuleWheelBase's isGrounded field works as expected.
A stock game is probably not be affected as driving and steering is still possible. MechJeb's heading control currently uses GroundContact but could be changed to check isGrounded instead.
I created a crude test craft (BG DLC required) that lifts and drops a set of wheels. Some method to watch the GroundContact value is needed, for example MechJeb (Rover Autopilot -> Waypoints -> Settings -> Rover -> Traction - percentage of wheels with GroundContact) or Kerbal Object Inspector.