Rounded corners are not clipped
When a UI node with border radius >0 is partially off-screen, the rounded corners are applied after clipping.
Bevy version
0.14-dev
BTW, at first I thought that this might be difficult to fix because clipping happens earlier in the pipeline. However, if the UV coordinates are correct for background images, then they should also be correct for rounded corners. So it might not be that difficult.
Just encountered this issue as well
Actually after testing, it seems it doesn't matter if a border radius is added or not. It's like the border of the overflowing child is overlapping the border of the parent.
See screenshot:
Edit: for context, I'm using bevy v0.14.1