This is is not necessarily an indication that there is something wrong with the knife or if it has been abused.
The good news is that they are not difficult to repair with a coarse water stone.
|Chipped Shun and Global knives|
Here is a quartet of chipped Shuns, practically new.
To repair the damage, you need to remove the metal along the edge, how much metal do you remove? Enough so that the chip disappears, you are going to basically destroy the factory edge and create a new one, a stronger one and it will be just as sharp or sharper than new.
Hold the knife on the coarse stone, 400 grit for example or 150 if you have it, take care, the objective here is to take away metal, there is no way around this. You cannot fill in the hole so you have to reshape the primary edge.
Grind on both sides of the knife at 40-45 degrees, and monitor the work by constantly visually checking, this can happen quickly, quicker than you think. Remember, you are not worried about making it sharp now, just making it useable again.
Once the damage is repaired, lower the angle to 15 degrees or so, this is a bit of guess work here so don't sweat it. Put 2 quarters on the end of the stone on top of each other and lay the spine of the knife down so it touches the top quarter, there is a good angle to use. Don't like that one, use 3 quarters.
Now you sharpen the knife, starting again with a coarse stone, 400-500 would be nice and then continuing through your progression up to 2,000 or 5,000 or just 1,000 if that is what you have.