So... I took some screenshot step by step, I hope that could help.
Ideally, when u create a selection with the lasso tool ore the path and u want to create a border to fill with the bucket, the selection it should fill up. Sorry for my english but is not my first lenguage, I hope you can understand something, but it seems that in the middel of the selection when I use the bucket tool to fill this selection (the secondo last), the color start to do something strange (its almost looks like the outer glow) and if I continue to fill with the bucket the border (last screen) that i create, the color comes out of the selection.
Hi, please can you give a more stepped eg of what you are doing, also if possible a screenshot with the feather and tools as appropriate. Also what colour are you trying to fill with (grayscale?)
The Border depends on the Selection but it is a pixel operation so the result can degernerate noticably, ideally you should probably just create a proper Stroke on a Shape Layer.