Hi Adeeb,
The solution for your use-case is a bit tricky because of various reasons..
- stopPropagation() invocation on the nested elements is not respected by the outer element's hierarchy
- stopPropagation() invocation will also stop the checkbox default event
Considering the above-mentioned points, I have drafted a workaround solution. I'm not sure about the quality of approach, but it's working as required.
- Add a custom style class to the Checkbox widget as highlighted below.

Demo: AccordionInsideListTask
Refer to the attached oml
I hope this helps you!
Kind regards,
Benjith Sam