Pretty sure its not a money grabbing exercise but a genuine bug, and if you've ever written or worked with code (thats also changed by multiple people), you'd know these things can be very tough to identify and fix, especially when you have other updates etc to push out.
Hopefully i'm correct and it is just an annoying and tricky bug to fix.
pretty sure it's not deliberate but a bug however going on previous bugs they rarely compensate. this one is more obvious because its costing players as opposed to mere inconvenience. if players refresh page after the ncp it will correct it I think before you waste gold and try again