As a rule of thumb, you never brush a coat of paint with the same or powerfull solvent on a previous coat of fresh paint. Most paints are hardening by loosing the solvent (which evaporates) and just a few by chemical polimerisation. Althought it will look dry, the process of drying may take a few days to end. To avoid this one should use solvent based varnishes over water based paints and viceversa.
Not all acryllics are waterbased. There are automotive acrylic paints that are thinned by solvents. It is also the case with Tamiya and Gunze which are containing a thinner that contains izopropylic alcohol (a thiner is a mix of solvents, while a solvent is is a chemical formula per se - like an alcohol or a hidrocarbure (toluen)).
So, if you want to avoid any problems you should follow a simple rule. If you have painted with water based paints (non etheric smell - Valejo, Ak interactive, even Humbrol acryllics) the varnish should be solvent based. If the paints are smelling, (laquers, enamels or solvent based acryllics), than the varnish should be water based (Future, Pledge, Valejo, Ak interactive etc).
Always thin down the varnish till it flows easy and give a wet surface when sprayed and make several passes to achieve a good and even coverage.