Greetings to everyone out there on the Misinformation Network.....
This is one of the reasons why veteran and prominent cue makers don't post more on here. Everyone is an expert and offers their theories which are in no way accurate. Instead of guessing and supposing what this may be, it would be more responsible to say that you just don't know or how about not posting at all. Do you really need to see your name up in lights?
Now for the accurate response:
This is not from any stabilizer (nelsonite or resolute) or anything that the cue maker did or didn't do. And, the cue maker was well within his rights to charge for another shaft.
Additionally....
Those stains are what is commonly referred to as 'tropical stains' or a fungus that is building up on the wood. This is very common on paper items from countries in tropical areas such as the Philippines, Hawaii and many British Commonwealth countries. It appears that the original poster is from the Philippines so I rest my case.
Futhermore....
The actual term is called 'foxing' which is closely related to epherema (look it up) items of which I am a collector of. You will see this on old collectible stamps, especially on old documents, envelopes and newspapers. Many Civil War Covers (mailed envelopes) from the southern states also contain this fungus due to the humid climate in the south prior to air conditioning.
Foxing can be treated effectively by neutralizing the acidity content of the paper or in this case the wood. And yes, we have the chemicals to effectively treat this but I have not done any paper restoration in several years. And no, I'm not interested in treating any cues. Depending on how severe the 'foxing' is, it may be able to be lightly sanded off. However, this is only a temporary fix as the fungus is already in the wood and will only grow back. The only way to rid it for good is to neutralize it. This foxing will not effect the playability of the shaft until such point where the 'foxing' becomes so severe that you are playing with fungus in place of the wood. That will take many, many years.
I would not store any other shafts or cues in the case you are using to store this cue. Rest assured that any cue stored in this case will become infected.
This is my Christmas gift to all you wannabe know-it-alls so now you do know-it-all.
In closing -- MERRY CHRISTMAS to all and to all a good night! Ho Ho Ho!