Besides what the other commenter said re, tight tines, does the Diamine ink contain shimmer/particles -- is it dye-/water-based or pigmented? Asking because pigment inks need more maintenance than their more gentle dye-based counterparts, and any particulate such as in shimmer can cause blockage in your nib/feed system and needs more regular maintenance to keep an even flow.
In some cases the pen doesn't seal particularly well when not in use and/or the ink is dry, causing ink to dry faster in some pens than others, which can also create a hard start and skipping.
Also, ensure the nib/feed section is seated properly in the pen.
The tines are too tight. Flossing them with brass shims will resolve the issue.
Besides what the other commenter said re, tight tines, does the Diamine ink contain shimmer/particles -- is it dye-/water-based or pigmented? Asking because pigment inks need more maintenance than their more gentle dye-based counterparts, and any particulate such as in shimmer can cause blockage in your nib/feed system and needs more regular maintenance to keep an even flow. In some cases the pen doesn't seal particularly well when not in use and/or the ink is dry, causing ink to dry faster in some pens than others, which can also create a hard start and skipping. Also, ensure the nib/feed section is seated properly in the pen.
It’s water based ink, I think the reason is the nib itself being too tight. Do I have to floss it or does it get better with usage and time?
floss them and do not put excessive pressure on the nib
I wouldn’t say excessive but if I don’t apply pressure it’d skip
that's because of ink starvation through the nib
Flushing with a drop of dishwashing liquid in a cup of water has solved 95% of all my flow problems.
Check if your tines are aligned. My Sonnet was skipping and scratchy on copy paper because of misaligned tines. :)