Hi sorry if there is somewhere else I am supposed to report this.
I installed latest version from asset store.
After applying some optimizations the TileHandler.cs had using Pathfinding.Poly2Tri at the top
But there is no Pathfinding.Poly2Tri. There is just Poly2Tri namespace. Wish I could be more specific what I did but anyway renaming to Poly2Tri instead of Pathfinding.Poly2Tri fixes for me.