No, syncing borders will not solve this, it will make it much worse. The pixels “bleeding” through are from an inner item. If I were to suggest a code to set the same border radius on that inner item, it will not match – because it is smaller than the outer container, and will cause a white line across the border on any major browser: https://i.imgur.com/5U9BhJE.png
I found this more recent issue with Safari, I think it might be related.
Based on what they suggest, this will get around the problem:
.probox {
isolation: isolate;
}But because this is a Safari bug, the things they suggested are just workaround hacks, so they may not work in all cases.
Please let me know if this actually works or changes anything.