2D Tilemap stretching

Hello! I have a problem with my 2d game. I made some 16x16 pixel tiles, and i made a little map using the tile palette. In the Scene preview nothing is wrong, but in the Game preview in some places these tiles stretch out. They become bigger and bigger. Some become 21x21 pixel. I pointed out some clearly visible differences in the attached pictures. + the little astronauts helmet is deformed. I have no idea what is going on, or why this happens. Could someone help me out? Thank you in advance!

Go to those blocks and press “Set Native Size”

I found a solution! Here it is: https://forum.unity.com/threads/pixel-perfect-2d-in-4-3.210497/#post-1513436