Safari: Image box captioned layout not following border radius

[legaspielaine]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce:

1. Add v2 image box block and set to Captioned layout
2. publish page and view in Safari
3. caption box (bottom part) doesnt get radius in frontend

Screenshots

Desktop (please complete the following information):

• OS: MacOS
• Browser: Safari
• Browser Version: Version 14.0.3 (16610.4.3.1.7)