A peanut butter with a visible oil layer on top is not pleasant looking. Perhaps you will refrain from buying this kind because you think that it is spoiled already.
The scenario does not necessarily imply that this peanut butter is spoiled. You can get a spoon and stir it and spread it to your favorite bread loaf. On the other hand, visible oil layer on surface will encourage rancidity (maanta) especially if the manufacturer is using a cheap packaging like the one shown below.
This cheap plastic container has a bad finish or lid and fails to provide an airtight environment for its contents. Presence of oxygen will promote rancidity (maanta).
Do not consume peanut butter with a bad smell or contains signs or rancidity.
Separation of oil is a natural occurrence. It will rise sooner or later because it is lighter than water and the rest of peanut butter ingredients.
If you still want a good looking peanut butter without the unpleasant oil separation, you can experiment adding an emulsifier like egg yolk, whey protein or milk.
Not comfortable working with natural emulsifiers? Choose an emulsifier from List of Philippine Permitted Food Additives, go to “emulsifier section”.