Quick fix is to pull the mag apart to CLP clean both the inside of the mag and the spring/follower, then tweak the spring coil right at the first coil coming off the follower downward to even the follower tension front to back, to get the mag to recover the rounds fully front to back against the feed lip.   Also, not a bad idea to check the bottom of the feed lips for burs that may need to be cleaned, as well as any casting burs on the followers when you have the mags apart to CLP clean them so the follower does not hang up on the inside body of the mag.

To add, double check the very front/top inside lip of the mag.  Most are fine, but sometimes you find a bur at that edge that may need to be removed as well (read may catch a bullet tip as the stack is rising).



To test the spring to see  if it needs to be tweaked at the first downward coil off the follower, just install 3 to 4 rounds in the mag, shove the rim side of the top round down and let the stack snap back up, then push down the bullet side and let the stack snap back up again. Either side test, the top round should recover to snap up fully against the entire surface of the feed lip.

As for tweaking the spring coil, pull the spring off the follower, use two needle noise pliers, and bend the first coil either narrow or wider right where it makes the 90 coming back around so the spring applies the correct needed pressure to the follower to recover the rounds front to back flush up against the feed lips every time.