I recently bought a Lamy 2000 FP. Great looking as well as writing. I am quite pleased. Except... The first ink I used in the pen was Iroshizuku Tsuki-Yo. Nice and wet, wrote wonderfully. Used up the ink, gave 'er a good flushing out, and put in Iroshizuku Fuyu-Syogun. Had it in there a few days when one day writing I saw all this blue ink on my writing hand. Then I noticed ink creeping out from the seam where the piston filler knob is. It's a blue ink, probably the Tsuki-Yo that I thought I had completely flushed out. I have never dropped the pen; it resides in a quality pen case. No drastic temperature changes. It never leaked with the Tsuki-Yo. Any ideas/thoughts as to why it could be leaking, and how to fix the problem, are appreciated. Many thanks!