Slow blink, not returning from sleep. WHY?

I know there are a lot of people suffering from this. I know that you can press the power button for a while, or use the pinhole, etc. I know all that. But I am asking about why the hell this is happening. I can't leave my desk for a coffee without thinking that maybe when I'm back half of my work will be done. And yes, I have all autosaves possible because, because of this I became a freaking paranoid of losing my work. But still it happens now and then and I'm losing my work, which means my time, which means my money. So my question is plain and simple. Does anyone know why this is happening? What the root cause for this is? I have all the Lenovo bloatware fully updated, all BIOS and everything up to date. But still it happens at least once a week, randomly. I go for a call, then I come back and it's like this. I go for a coffee, I come back and it's like this. I can't see any pattern. Sometimes it happens, sometime it doesn't. Any clues? I'm desperate with this.