Summary
The documentation for unnecessary-call-around-sorted (C413) says:
This rule's fix is marked as unsafe, as reversed() and reverse=True will yield different results in the event of custom sort keys or equality functions. Specifically, reversed() will reverse the order of the collection, while sorted() with reverse=True will perform a stable reverse sort, which will preserve the order of elements that compare as equal.
That makes it sound like the fix is always marked as unsafe. In fact, it is marked as unsafe for reversed and safe for list.