Lint is everywhere in our shops and we strive to keep it out of the printing process, but some shirts are terrible and some not so bad, but it really is unavoidable.
Beside diligence, there are answers. When we have very long runs and particularly with very linty shirts, you can print a base screen on a high mesh with a clear base, with speed, angle, and pressure to put down as little as possible. The lint then is both picked up by that screen and the clear mattes down the lint without really affecting the hand. Also clear is cheaper than ink and your ink sinks in less and therefore reduces your cost slightly.
Luckily we spotted this spot pretty quickly today, minor damage, but if you are on cruise control and asleep at the wheel you can lose lots of shirts. Keep your eyes peeled, shops clean, and consider a clear base.