@Paularhion Without more photos it's hard to say but to me it looks like the converter isn't seated fully or it leaked around where the converter meets the section.
My only FPR pens are piston fillers (Jaipur v2) and eyedropper (Muft) so I am not terribly familiar with their converters.
Maybe a little silicon grease around the tip of the converter might help it seal there if that is what happened.
Heat setting the nib+feed may also help if it isn't back far enough. FPR has videos for that.
@Paularhion Without more photos it's hard to say but to me it looks like the converter isn't seated fully or it leaked around where the converter meets the section.
My only FPR pens are piston fillers (Jaipur v2) and eyedropper (Muft) so I am not terribly familiar with their converters.
Maybe a little silicon grease around the tip of the converter might help it seal there if that is what happened.
Heat setting the nib+feed may also help if it isn't back far enough. FPR has videos for that.