These are beads, droplets, larger globules or "curtain effect" in the paint finish on vertical surfaces.
Ensure that you always adapt the mixture of paint with the correct choice of hardener, thinner and viscosity to suit the temperature and size of paintwork. Ensure that the spray gun is clean and with the correct size of nozzle and air cap. Spray in an even pattern and do not hesitate with the gun or arc your spray pattern.
When the paint has thoroughly dried, remove the run with the correct choice of sanding block/denibbing tool using a carbon block or wet sanding paper. The finer the paper, the less damage to the paint and the easier to polish. Polish with Glasurit Fine Polishing Paste 562-1602 and finish with any standard deep gloss polish.