I own a Tibaldi Modello 60. Today, I noticed that the pen was writing dry, and I thought that maybe it was low on ink. I emptied the pen (it still had plenty of ink, so maybe the nib just dried out a bit). But, when I turned the piston to remove the ink and to rinse the pen, the nib unit turned along with the piston each time I reached either the fill point or the empty point. This worried me. I emptied and filled the pen with water several times, and each time the nib unit turned. The last few times I emptied and refilled, the nib unit remained stable. Does anyone know what might be going on? The pen seems to write okay, though I noticed that ink leaked into the cap. I don't know if that happened after I refilled it with ink today, or if it leaked on the prior fill. Thanks, Susan