If you just flushed the nib, then most likely what you are seeing is water, and not ink. Especially if you flushed with something that adds a little force, like a bulb syringe.
The pen is filled with a converter. So under normal circumstances, the converter attaches to the feed nipple on the back of the nib housing.
This will completely isolate the ink from the outside of the housing.
So unless there is a problem, your ink will not find it's way to the outside of the housing.
But the water from flushing can find it's way to this location.
And as others stated, this is completely normal, and even if this is ink, no real harm. A normal flushing routine would remove the ink. You are just seeing through an acrylic that is translucent enough to show this. If it bothers you, then you can disassemble everything as shown above, and then completely dry everything, then re-assemble.
Edited by bgray, 28 April 2014 - 22:53.