They spawn lots of fighters if that's what you mean. They shouldn't be spawning bigger ships except at the start of the battle, to my knowledge.

no keeps spawning big ships vents victory ISTD and don't stops

I've got this one too. On Telos My Rebel base apparently had 10 dreadnoughts, 8 Light Assault Frigates, and a number of regular bulk cruisers and bulk cruiser/carriers, then came the Nebulon-Bs but no corvettes for some reason. Probably because the enemy keeps retreating before I even engage. Then on Allyun it had dozens of MC80s of various types in reserve and they just kept coming. Are the defense fleet supposed to scale in relation to the enemy fleet or something?