Every Uniball Jetstream I've owned is scratchy

I've used uniball Jetstream pens on and off for last few years. Most of them start off relatively smooth but very quickly start to write scratchy.

For example, in the picture attached the blue writing is from my Jetstream SX-210. I only started writing with it yesterday and there's plenty of ink left in the cartridge.

Anyone else had a similar experience? Seems to happen with 0.7mm ones too.