how so?
are you talking about after you separate and just leaving the solvent in a jar for a few hours?
swim is by no means an expert, but based on swims readings it shouldn't be a problem, swim personally left his solvent in a jar over night and didn't have a problem.
now if your are planning to leave the solvent in with the plant material swim believes that more plant fats can seep to the solvent layer ( but not in 3 hours) , again swim is not an expert and could be wrong but just over what he has read, can any one verify this