Cedar glulams sure aren't common, and it wouldn't have been all that wise to use one in an application that involves much load. Southern pine and fir are the industry norms in the glulam business (fir is the norm in your neck of the woods, and southern pine is the norm in the eastern half of the USA).
I can't imagine that the checking would be in more than one of the laminations unless this thing was home-made by someone that didn't use dried lumber. Can you provide a pic?
If the glulam is structurally compromised by the checking I don't think that epoxy is going to help much, at least in the lower 1/2 of the beam (the tensile portion).