Im playing on version 0.15.37 non-steam version and I found a bug that I had to restart my PC in order to make it go away. First I want to say is when Im zoomed out and scroll my mouse over a building, all three types, the preview that pops up of whats inside the factory pops up but it flickers very fast. The flickering stops when I zoom back in a bit more or move my player towards the building but this time it didnt do that. I was checking around my factories checking what is done and isnt done and the flickering started and never stopped. I even had my mouse away from the building but in my upper left corner of my screen the preview was still there flickering. I first went into my game settings to turn it off and that didnt work and so then I tired closing the game but the flickering of the preview was on my screen still! So the only other thing I could think of was restarting my PC and this worked. Im glad I didnt have to send my PC in to get it fixed all because of a weird glitch/bug with the preview. I didnt think to take screenshots of the glitch/bug because I was more worried about how the heck I was to get it off. I was playing on singleplayer and my PC can very easily hold massive factories in these buildings just fine so its not a internet or PC strength issue. Whatever caused this bug/glitch its not on my end because it still stayed on my screen after I closed the game out completely, I even checked my task manager.

That's an unfortunate interaction with Factorio's GUI system: Custom GUIs block the mouse from hovering over machines. So if you hover over a factory building in the top left corner of your screen, then the preview will pop up and block the mouse from seeing the factory building, so in the next tick the preview will disappear because the mouse isn't over a factory building anymore, which in turn causes the mouse to be over a factory building again, repeat forever. That's what causes that flickering. If this happens often and annoys you, you could try making your preview window smaller (Options -> Mods -> Per player).

The flickering after closing the game might be related to this factorio bug report, as mods don't really have enough control over lower level rendering to cause that themselves.

https://forums.factorio.com/viewtopic.php?f=7&t=46754

It might be good to report this bug there to help the factorio devs fix it.

The out of Video RAM explanation the dev suggests makes sense for this as well, as the preview window is an entire new surface for factorio to render. You might be able to change the video settings to keep it from happening as often.
(and the flickering preview is probably compounding the issue causing massive VRAM swapping and the GPU can't keep up, but probably nothing modders can do about it).

Oh, I see, so this isn't actually caused by the GUI thing, but an actual rendering issue? Yeah, I should maybe have read your comment more closely, bearcoco22. Sorry about that.