Question Issue with isometric Z as Y tile palette

Heya. So, I got this tile palette and I'm trying to add a tile that actually occupies two cells on the grid.

Every tile is 32x64, except for the big mountain which is 64x96. Because of the extra height, the tile won't display properly in the grid. Is there a solution to this? Maybe a better way of doing it?
Any help is appreciated.

 

Did you check the sprite pivot point? It seems it's too high up to me. If the highlighted tile in your palette is the one with the mountain, it's not at the base and so the sprite sinks down.