I'm a long time GC player and I'm enjoying GC IV right now, but there are two glitches I've come across in my first full game.
1. Playing as the "Cosmic Contanimant" whenever I park a ship called the "Pest Mother" (a species ship you can assign a commander to) at any Starbase, it gets stuck there. There is no way to eject or tell it to move off the starbase. I've tested it several times, tried different types of things in different conditions to see if I'm missing something, but it appears to be a glitch.
2. Playing as "Cosmic Contanimant", when I teleported a Korath fleet that was laying siege to the planet "Gienah III" to a random area of the galaxy using a module in my vault, so that I could seige/invade instead, the game still thinks the Korath are seiging and states "World is already under seige", BUT it is not. So, it appears to be a glitch.