Right now when you choose One Color, if you play any One Saber map the saber is incapable of hitting the blocks even though they are the same color. Rather than fixing the SaberType, OneColor should basically do nothing when playing a OneSaber map.
There should already be a guard in GameModifiersBehavior.cs
GameModifiersBehavior.IsTransformNecessary()
That checks for the One Saber mode by map mode name "OneSaber" and will prevent the need for a transform. Perhaps the name of the mode has changed since then so some debugging is required.