There are many reasons for aggregation.  To simplify it, imagine there is the ability to formulate an equation to determine if and how much proteins will aggregate and at what concentration.  The formula would have many inputs.  Glycosylation is one of the many inputs that would determine whether a protein will aggregate.  In the case for monoclonal antibodies, as touched upon in an earlier question, glycosylation can affect stability and solubility.  If a monoclonal antibody is less soluble and less stable, then it will have a higher propensity to aggregate.  Furthermore, glycosylation also affects the folding of a protein.  In cases where the protein is mis-folded, the protein would also have a higher likelihood of precipitating.  While glycosylation can play a very important role in aggregation, it is one of many components.  Therefore, the amount, type, and location of the glycosylation will also be relevant.  How the aggregation equation is formulated may vary for each protein, but the basic inputs will be common between the equations.  Glycosylation and aggregation are related, but to what degree and how much would likely depend on your specific protein.