Just upgraded Able to 4.16 and it wasn’t too crazy (4.15 was WAYYYY worse). Change your Build.cs as others have shown, and fix up any now deprecated method calls.
@Sveitar, change your Add to AddUnique and you can filter out duplicate entries at that level. Granted the behavior probably shouldn’t have changed, but still - at least that will keep you going.
PlayableMaps.AddUnique(AssetList*);