Hi Martin, 

sounds like dust to me.....just hard to tell how bad it really is.  i have done briteside finishes and upon really close inspection, have dust imperfections.

if you had classic contamination - you would be getting crackling or some other effect like holes or obvious bubbles.

for me, in addition to a clean shop, time of day (e.g., early morning or late evening when there is no win) or after rain has cleared the air of pollen have sometimes helped.  

while i have not personally buffed out briteside, and apparently not recommended by the manufacturerer, there are those who said they did it and got great results.

https://www.clcboats.com/forum/clcforum/thread/47449.html#:~:text=Interlux%20doesn't%20recommend%20buffing%20Brightside.

h

   Just a matter of note I have buffed Progressive plus, and captains varnish with great results. Sand with 1500 last before using polish compound, make sure you do not see any sanding swirl marks.  I have learned unless you have a negative air room, dust and bugs, are part of the process.  If you don't have an right angle grinder with a 7" or 8" pad you can rent one.  Makes the job much faster. The process is fas,t you are just taking the dust off not he varnish.

   Thanks to you both! I'll try buffing at least, can't see how it'd hurt bad enough that another coat couldn't fix.