[2020] The kill cams have always been iffy, but I’ve never grown another pair of arms in them before

They are fickle beasts sometimes. Just to further support what Thanos_dad is saying, we actually wrote about that in a community update back in August. Check the section under " How Killcams Work" - https://www.reddit.com/r/CallOfDutyMobile/comments/iigbzk/call_of_duty_mobile_august_28th_community_update/