(It’s not clear to me if this post will reach your notifications on lemmy, but I’ll give it a shot) aside from replacing the converter, you can try dabbing silicone grease on the screw threads where the section attaches to the barrel. This is how pens are waterproofed for eyedropper filling.
It’s not expensive; fountain pen shops sometimes stock it but so do other crafts supply places.
@Unattributed @penfount did they blur the branding on the pen? definitely something very legitimate going on here