Why Bunkers are not consistent

 Today's golfers are accustomed to such wonderful playing conditions that the most frequent complaint about course conditioning is actually involving a hazard,

"The playing surface in bunkers"

 This occurs despite the fact that many golf courses allocate significant resources to maintain bunkers in near perfect condition. A good argument can be made since

the bunker is a hazard,

inconsistency in the sand is a reasonable expectation. In reality, consistency is impossible to achieve anyway, since bunkers are not uniform in shape, size, or depth and the sand itself changes over time. Sand depth varies throughout the bunker, the sand is deeper in the bottom of the bunker and shallower on the sloping bunker face.  The minimum recommended sand depth on the bottom of the bunker is 4". Attempting to maintain this 4" depth on the bunker face may result in "fried egg lies". A condition so named when a golf ball becomes embedded in the sand. Since there are varying sand depths in bunkers this results in varying moisture levels in the sand and varying moisture levels quickly impacts the sands playing quality.
 For example, many bunkers have steep sloping sand faces that are difficult to maintain. During heavy rains, the sand is dislodged and replaced the sand is loosened and more proned to "fried egg lies".
 In contrast, undisturbed sand produces a much firmer surface. When sand is washed off the bunker face it mixes with the underlying soil, which changes  playing quality. Eventually this results in poor drainage and bunkers that may end up looking like a water hazard.
 Ultimately, it's impossible to achieve consistency and playing quality from one bunker to the next. Skilled players learn to develop a feel fro the condition of the sand and adjust there shot accordingly.