If you are getting small white deposits then there are 3 possible reasons for it:
1) Too thick an application.
2) Damp weather.
3) Varnish needs a good shake as it has settled and separated.
I have never used Army Painter varnish so I am not sure if 2 and 3 are applicable.
I only use D-R Soluble Matt varnish now that the dependable Blackfriars formula changed. With D-R it is give a good shake, do a test figure, keep shaking, if test figure ok then proceed but only 3 or 4 figures at a time before giving the bottle anothe shake.
Orctrader separates some of the carrier from the bottle but I have found I don't need to do that.
I have only had 1 figure out of around 500 get the dreaded white speckle, that was because I was in a rush and applied it too thick.