ProximityPrompts have a 1px gap when using the standard UI
To reproduce, insert a ProximityPrompt and hold the interaction key. Once the circle goes past 50%, you’ll notice the gap. This might depend on your screen resolution or camera angle, etc since it is likely a rounding error.
Yeah, this only happens when using a lower res device (usually a phone)
I believe this is because that element uses an image, so obviously it would be downscaled to scale to the screen resolution.
Image downscaling does not mean things become unaligned by 1px - this is almost always a rounding error caused by human error.
For example, Guis have AbsolutePosition which returns a decimal. You have to round the value to figure out which pixel it’s rendering on - but some people assume you can just drop the decimal, which leads to issues like the OP.
Thanks for the report! We’ll follow up when we have an update for you.