That is not enough tiles for a 3x3 minimal bitmask. i think it finds no suitable candidates so it picks the last suitable one it finds, which I think would be the 2nd tile on the 1st row in the bitmask image.
Here is an image of a full 3x3 minimal autotile bitmask:
The 6th tile on the 2nd row would be chosen if you had the full bitmask available. Without a full bitmask worth of tiles you will have to do manual tiling to fill in the gaps.
There is some priority property you can set to chose one tile with the same mask over another but I'm not 100% certain on how to do it so I'll leave the answer open for someone else.