PlayStart disrupts the position of objects on the map

I created a map for my drone, as shown, I placed each cube in the middle of a grid on the ground to allow me to calculate distances.
But when I created a spawn point PlayStart for the drone, when I clicked Play, I found that the drone didn’t appear in the expected position and the cubes I had placed in the middle of the grid were shifted from their original positions .
I tried restarting the project but the problem is still there, and I’m stuck now. What am I missing?
Thanks a lot!