My grandfather had a saying about building steps: "The feet remember."

So why is it that the 1" shorter riser onto the landing at the top of a
staircase in a vacation rental I'm in hasn't bothered anyone? I didn't even
notice that the riser was 1" shorter until I actually noticed it with my
eyes after being here for 5 days. 4 of us have been sleeping upstairs and
using the upstairs bathroom all week, so we've been up and down the stairs
countless times.

I think I know why it hasn't bothered us and I did a little test with my 2
adult sons to see if I was right.

I watched them both go up the stairs and they did the same thing that I
realized I had been doing all week.

When we reach landing we have to turn right to go up 2 more steps to reach
the hallway. As we step up onto the landing, we take a regular stride,
which puts us in the middle of the landing. This allows us to take the same
size stride all the way up. In other words, the shorter riser onto the
landing allows us to step farther onto the landing, making the transition
to the next steps easier.

Is it possible that the builder had this in mind when he built the steps?

After a week in the house, I'd say that it is pretty well built, with some
nice built in features. It doesn't seem like the short riser could be a
glaring mistake in an otherwise very nice house.

Could it have been done on purpose to make the turn on the landing easier?