Pete ... when you say "star shaped" bruises ... is the fiberglass indented in the center of the star ... or does it appear more like a spiderweb?
Also can you see any cracks coming from under the other two globs of grey expoxy?
Are there any fixtures inside the Oxygen
that attach close to where you found the gobs on the roof?
Can you take and post some pictures?
But basically, if your "stars" are just spiderweb cracking, that is usually more cosmetic rather than structural ... and will never leak. Boat stores offer a number of kits to fix spiderweb cracking in boats (so you might go to your local boating store and ask for their opinion.)
If the center of the stars is indented, it's possible your rig was damaged during shipping or on the dealers lot.
Since you bought a "new" trailer ... I'd take it back to the dealer and get his explanation. Please also let us know what he said.