Camera background glitches, drawing multiple images of gameobjects on the background

I ran into a problem with my current project where I have the Main Camera set up with only a background color and the color alpha set to 1.

I change the background color with a script every 5 seconds, where I just randomize the background color with RGB values and set the alpha always to 1 (max).

Here's what it should look like (tested and working on multiple devices, including my OnePlus One):

And here's what it looks like on a single device (my friend's Huawei P8 Lite) so far with no fix:

So what happens is the camera background just draws everything multiple times, an error that I've seen in some engines (Unreal, Source) when the camera has no texture to render on the background.

The problem has occurred only on this one device, and I've tried searching for help but honestly I'm not really sure what to be searching for. I'm pretty sure it has something to do with the camera having transparency and no background image/texture, but no idea how to fix this for just a single device without changing how the background color works. I can't replicate the issue with the devices I have available, so I can't really fix it by trying stuff out.

I'm running Unity 2017.1.0f3 personal edition.

Any ideas? Settings on the camera or anything? Thanks in advance!