Prop movement on 2018 40hp Merc

I've got a 2018 40hp Mercury that was new when I bought it last year. Until now, I had not paid much attention to the prop, other than making sure it has never hit anything. It hasn't, and the engine runs great.
Today, I had to move the boat into my shop to keep the dadgum mice from setting up home where I had it parked under a lean to next to my shop.
Anyway, I noticed the prop moves back and forth on the shaft about 3/32".
So, I removed the prop nut and nut retainer and checked the forward thrust hub. The hub is oriented correctly. I put it back together and torqued the retaining nut to the prescribed 55 ft lb. The prop still moves back and forth 3/32".
First question: Is the prop supposed to move back and forth like that?
Second question: If it is not supposed to move back and forth, what can be done to remedy the issue?

Thanks.

My mechanic told me that’s normal.