Even though the target pool is directed at village buildings, streets can randomly generate from the other side of the block.

/setblock ~ ~ ~ minecraft:jigsaw[orientation=north_up]

{name:"minecraft:building_entrance",pool:"minecraft:village/plains/houses",final_state:"minecraft:structure_void",target:"minecraft:building_entrance"}

set generation level above 1

I noticed this almost always happens when the block is placed on top of trees, for some reason.