The fix version says otherwise.
Well, it's wrong. One of the nice things about Yetus is that it reveals quite a bit about what is happening. Yetus switched to 2.8.2 based upon your patch name:
HEAD is now at 5cf6a1a YARN-6805. NPE in LinuxContainerExecutor due to null PrivilegedOperationException exit code. Contributed by Jason Lowe
Testing HADOOP-14521 patch on branch-2.8.2.
and then processed these lines https://github.com/apache/hadoop/blob/5cf6a1af0f1d1abdd7e9d29d5b427d554991c7dd/dev-support/docker/Dockerfile#L83-L85
which then blew up.
Note that the git hash that was switched to and the github reference match. So, no, this fix isn't in 2.8.2. I suspect what's in 2.8.2 vs. what JIRA thinks are in 2.8.2 is wildly wrong, again, because the branch was cut way too long ago and most people don't realize that branch-2.8 is actually 2.8.3 now. It's a mess generated by aggressive RMs that then fall off the face of the earth, but it doesn't appear the PMC really cares about this problem enough to put an end to it. Given that 2.8.1 was voted as a valid release almost 2 months ago and still hasn't seen the light of day says a lot.