I keep coming across the same problem.
In the final stage of flatting and polishing minute white speckles appear in the epoxy.
My process, 1 st coat , coating epoxy , 8 > 10 hr cure @ 20*
hand 120 dry sand , brush off dust , vacume.
2nd coat , coating epoxy 8 > 10 hrs cure @ 20*
hand sand wet - 320 > 600 > 1200 > 1500 > 2000
everything looks good at this stage even flat finish no blemishes really, just needs buffing up...
so
machine polish - ( cheap electric car plisher ) onto wet surface - farecla standard compound G 3 ( SPECKS APPEAR  

> farecla ploshiing compound G10 ( SPECKS REMAIN )
it does not always happen but it doeas happen a lot
any ideas
Ben