Why do characters keep talking after dying, and how do I fix it?
I don't think I was having this issue before enabling subtitles, but after enabling subtitles, I am frequently seeing others doing the same too. Try disabling subtitles, that might solve the problem.
It's a bug. Bethesda may patch it in the future, although I've seen it (in the PC version) too, and there doesn't appear to be any way to fix it except on Bethesda's end.