when I use future lighting and turn on shadows, the floors turn white and start glitching out like crazy. https://streamable.com/qqqof4
at first, I assumed it was an issue with the textures, but it seems to be glitching on other parts as well
any ideas what the issue could be and how I could fix it?
This is clipping. you have 2 faces in the exact same place. The renderer doesn’t know which one to show so it shows this weird glitchy effect. If the 2 clipping faces are 2 seperate objects move one of the 2 a tiny bit. If they are one (A mesh for example) you would have to move one of the faces a bit.
how can I replicate this issue?
I think you mean you want to fix the issue? In that case simply move all the faces which are in the exact same position by simply selecting and deleting the face which it decides is on top, if that was the wrong one, move it over and delete the other part then put it back.
i don’t understand which face you’re talking about, so I was asking to replicate it so I could understand.
im not sure if you’re referring to face on the light part or the floor?
Actually my mistake, @xaIency is wrong in this case as you can see by the character also clipping. What’s your light intensity? Global shadows?
yes, global shadows are on 
How about the lights themselves?
Also, wrong forum. Game Design is related to actual gameplay elements, not these kinds of glitches.
lights have shadows too.
i turned global shadows on and off again and the issue started happening in studio (rather than before, just in-game)
That’s weird, seems to be a bug, I’d take it to #platform-feedback:engine-bugs.
ok, thanks. the forum said to get help with issues so I thought it went here my bad
This is actually an effect called z-fighting. @xaIency pretty much described the problem accurately.
Your game has 2 parts that are either the floor or on the floor that have the same height. My best guess is that you have one part that is applying the tile texture while another part is responsible for the concrete texture.
the texture parts are inside the concrete part, could that be the issue?
Yes, that is most likely the source of the issue.
That is not the character clipping. Light bounces off of the ground and gets reflected onto the character, but since the floor keeps changing due to the clipping the light changes in power and color too.
After heavy testing, it seems that if you have two light parts together, the game won’t know which way to cast the shadow. Originally my lights had two parts, each of them having a PointLight. They were less than a stud apart, making them really close. 
To fix this, I removed both PointLights and added a part in the middle that had the light attached and activated shadows.
edit: textures were not an issue with the lighting
I came here because I’m having the same issue and none of my pointlights are closer than a stud apart, they’re not even close to each other.
I did more testing and it seems there are a few different variables that are causing it. For me, it had to do with 1) how close the pointlights are and 2) how many there are.
I noticed while redoing the lighting, that I only began having issues once I exceeded a certain amount of these lights. I noticed issues probably around 100 pointlights and my game has about 300-350 fully completed.