That is not micro foaming. Micro foaming is very, very tiny holes across the entire surface.
Best guess looking at the pictures you are spraying to heavy.
Don't wet sand, unnecessary. Sand between coats with 240 or 320 Granat. I use the ETS 125, DTS and RTS to sand between coats.
Just shot these. KA+ White Mid Gloss, tinted to match BM Navajo White, thin 2% by volume with GF Enduro Extender. T-70 bottom feed, 1.0 mm air cap set, can't tell you how many turns out on the needle, I set my gun by sound. Shop temp is somewhere around 65ºF.