selling stuff on npc

i recently notice that if you sell item on npc sometimes doesn’t receive gold it happens random. please investigate this issue thank you.

Hello, can you let us know what items are having this bug?

currently im farming gold, so selling a level 4 skill books is a good income.
the item is skill books level 4.

Thank you for the info, we will monitor this particular case.

We appreciate your time in reporting this matter to us.