With 4 coats of clear you have something to work with, so the first thing I would do is sand the panel or panels with 1000 on a firm pad, but don't try to sand the spots out, just sand as if they are not there. Afterward, clean your panel or panels with wax and grease remover, concentrating on any little holes you may have. Then you could mix up a very small amount of clear and dab it in the holes with a toothpick, end of a paper clip, or small brush, leaving the clear spots higher than the surrounding area. Let these dry overnight, then block them down with 1000 until level. Trying to sand those spots all the way out will leave you with burn throughs or thin clear. I'm with Shine on it looking like moisture, especially those 2 top spots. The bottom one looks like air born contamination causing it to fisheye. Neither look like solvent pop. When spraying in less than ideal conditions, these types of problems will happen, and you just have to correct them.