I have been buying this boot for years and they always crack across the sole after 6 months this is true.
That being said, they are the best boots for the price. They should not be pulled from the shelf because I have had $150 timberlands fall apart in less than a year.
I tend to blow through the toe's so I install rubber toe protectors on every new pair. The cracking sole is annoying but dose not affect comfort. Only waterproof issues are a result of the cracking when standing in water over an inch deep. (Shouldn't be a problem for a stock clerk.)
This review was written by a plumber... And I abuse all of my work gear far more than the average person.