The above answers regarding Setback are correct. It's usually the result of repeatedly chambering and reseating the same round, and can result in a unsafe round. It will vary, depending on the individual weapon, and the particular cartridge's crimp.
Since I carry in Condition One, but store every night in Condition Three, I keep an eye on Setback in my EDC rounds. I just place them upright in a row on a flat surface, and use the spine of the magazine as a straight edge along the top. Any round that doesn't make contact at the top goes to the bottom of the mag when reloading. Any one as severe as the example in the OP would get tossed- since I make it a point to get to the range at least once a month, at least to run through and replace my EDC rounds, I never see it as bad as that.