Dying of maduro wrappers is not an indication of wrapper or cigar quality. Wrappers are dyed to provide consistency and usually used with a naturally fermented wrapper. Heat fermented wrappers are more consistent in color as they are cooked. Natural maduro fermentation can lead to inconsistency. Sometimes this results in blotchy wrappers or differences in color from one batch to another.
Staining on the end of a cigar is not an indication of dye. Dye would only show on the outside(wrapper). Staining on the end is usually a buildup of tar and can occur with any combination of wrapper, binder and filler, not just maduro's.
Usually recutting and a good purge can reduce the tarring of the end of your smoke.
