Woodland mansion second set of stairs are two blocks wide, despite opening being three blocks wide

The bug

Despite the opening to it being three blocks wide, the start of the stairs in woodland mansions leading from the second floor to the third floor is only two blocks wide, causing them to be off-center.

How to reproduce

Can be easily seen in any woodland mansion. Screenshots provide a seed and coordinates if absolutely required.

Expected results

The stairs would begin as three blocks wide as to align with the mansion more correctly.

Actual results

They start at two blocks wide, causing this weird, mismatching architecture.