This is not a bug but *might* be considered an exploit. Try it and let me know what you think.
I started a new Medium galaxy with Mercenaries included. Found the Bazaar reasonably early. Bought "The Anvil" mercenary ship which gives you a transport ship with 5 legions before you have the Planetary Invasion tech.
Subsequently made a bee line for and then wiped out 3 minor civs and 2 major civs, taking 7 planets in just a few turns. None of them were defended, even though some were civ homeworlds. After that, i used the same Anvil ship with a few armed escorts to knock out two other major civs that did have light defensive fleets.
At this very early point in the game, most worlds are not defended at all. With the Anvil and a few armed escorts, you can catapult yourself into an irresistible early game lead that is hard to lose.
In pre-Crusade GC3, this might have given you an early planet or two. Because you can just recycle transports and legions now, this one ship gives you a ticket to mow down a large swath of the galaxy before anyone can defend themselves from it.
(This is my first game of Crusade and the last time i played was about 2 years ago. I am not an expert. If i knew what i was doing, i'm sure the damage would have been much greater.)
Thoughts?