Why is there a weird line in this Bridge in Zone builder?

[Octosquid]

I was working on my map and there was this bug!
Its not there in Zone Builder and I haven't made a new sector.
Can someone help me?

(sorry if I did anything wrong, I'm new here)

 

[SeventhSentinel]

This appears to be a pretty common issue with the OpenGL renderer. It has a reputation for adding holes in places they shouldn't be. You can try moving the vertices of your bridge around a little bit to fix it, but I wouldn't worry about it as long as it looks correct in the software renderer.

 

[Octosquid]

Thanks! at this point I've decided to just remove the platform to the left to make it a jump. I mainly use OpenGL so my level may look better in that renderer and I didn't want any issues.