I just recently got into 3d modeling because i wanted to make mods for a few games. Currently i’m stuck on using subdivide to divide a wall of a building. When subdividing the wall, the adjacent wall’s median point shifts towards the wall that was just subdivided. The point shifts more and more as the number of divides increases. Is there an a way to change this or another way to go about this? Help would be very much appreciated!

Example:

(Little bit hard to see, the top shows the move better)