You got me curious, so I brushed up on some basics regarding this issue. Split wrappers are due to slight overhumidification. When your cigar is lit, then poof!
Wet tobacco leaves will swell as they absorb moisture and the wrapper may split. A split wrapper spells the end for most cigars. (We've seen some unique shapes and sizes after desperate people have cut the ends off of their damaged sticks.)
Moderate over-humidification may result in interior swelling, the appearance of plume and possibly mold. If you catch the problem before mold appears, you should be able to fully revive your smokes without permanent damage. If mold appears, you should take immediate action.