Question
Greetings David

After a close visual examination on my Robellini I noticed a yellowish brown
stain on the leaf very close to the crown, (Thought it could be LY at an early
stage ?) But what do I know..

Anyways, Im concerned the palm could die. Mind you the Robellini is a
doublet, in Miami FL, and all 11 other doublets have no discoloring or
yellowing. This one is in a particular enclosed area where there is possible
shortage of nutirients and possibly water too.

Answer
I would check to see if there are any insects on the stem of the palm.  The yellow stain could be honey-dew from scale insects feeding on the plant.  Or-- it may be plant sap coming from a wound on the plant.  Try rubbing the stain off and see if it comes back in a day or two.  This may be a sign that it is some fungus.  I doubt that what you are seeing is caused by lack of water or nutrients even though the plant may be stressed from these factors. Let me know what you find.