It seems to happen when I enter a new area (medbay, computer center etc), when there's multiple enemies on the screen, or when I'm firing one of the new fancy weapons, basically whenever a lot is happening. But it also sometimes happens randomly when I'm going through an empty corridor.
Hey, I have found the lag problem and have fixed it. Please let me know if it works for you. Also, thank you for buying the game, and I'm really glad you're enjoying it!