Legend of the Galactic Heroes is a series with many episodes in which "...two interstellar states...are embroiled in a never-ending war...focuses on the exploits of rivals Reinhard von Lohengramm and Yang Wen-li, as they rise to power and fame in the Galactic Empire and the Free Planets Alliance..."
I've had that same problem. Thought I was the only one. It almost seems like some event interrupts the process of going to sleep. I've tried being really careful not to move the mouse after I've selected sleep from the menu. Also, I make sure to turn off my Bluetooth headphones prior to selecting sleep. Seems to help but I may just be imagining it all.