Comment 2 for bug 1569446

Currently xtrabackup 2.2.13 is being installed.
The most recent stable release is 2.4.2.

The only really interesting thing I've noticed so far in change logs between versions was the innobackupex script being rewritten in C (2.3.1-beta1).

https://www.percona.com/doc/percona-xtrabackup/2.4/release-notes.html

Still need testing to see whether using a more recent package has any effect on this issue and what else would possibly need to change in configs or when upgrading.