Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I noticed your question had not been answered, so I thought I would ask first: Do you insist on being helped by Expert Rusty? or may I offer advice on this pair of problems with the Korg keyboard you mention?
The pressure pads may have to be replaced, if some are louder than others. This can be owing to dirty, or compression with age, or even 'sagging' of the pads springy qualities.
But also, it can be dirt, simply. Spraying in between the keys with an air compressor of the type used to inflate tires, sometimes with adjacent keys pressed down to let more air into the keyswitch area, permits 'repair' of a dirty keyboard with irregular key performance.
The second issue is more abstruse... I'll have to look it up, to be honest.