I suspect it's related to this:
Some guns tend to push the bullet deeper into the casing when the round is chambered. Differences of a few 0.001s of an inch in the shape of the chamber or depth of the rifling can cause this. If a bullet is pushed further into the casing, it might be held tighter by the casing crimp. It would then require more pressure to get that bullet moving, which might result in a misfire or other malfunction (bullet stuck in the barrel, failure to fully cycle due to less recoil, etc.). I have read that in extreme cases, the bullet got so jammed in there that its resistance exceeded the rupture strength of the casing, resulting in a catastrophic failure. (Theoretically, guns with chambers that are not fully supported (such as Glocks) would be more vulnerable to this.)
You can check if your gun does this by repeatedly chambering and ejecting the same round, then comparing its overall length to a fresh round (or measure it before and after with a caliper if you have one).
You make yourself most vulnerable to this if you constantly re-insert your ejected round at the top of your magazine. This allows the same round to be loaded/ejected over and over. To avoid this, I'll pop several rounds out and put the ejected round further down in the stack. But I'm not clearing my weapons every day. In situations where you clear your weapon often, it might be easier just to relegate the ejected round to the range bag than to keep track of which rounds have been chambered and which haven't.