innobackupex failed at

I have been using innobackupex for a while on a number of databases, but today I faced an issue which I haven’t seen before.
During initial backup of 470Gb MySQL database innobackupex fails with the following error:

I tried to make a backup on a local disk, on nfs mount and using nc. I tried to do it in tar.gz, tar and raw files.
Every time it failed somewhere at the end of the backup process, because resulted files are almost the same size as an initial ones.

Appreciate any help there.
Thank you.

By any chance you might be affected by this bug

Thank you.
It is exactly what you have highlighted.
I have found the workaround for this issue:…assertion-bug/
We are optimizing our database in order reduce used space and run “Alter table” or “Optimize” commands, since they will take a long time.

As an update: Method I have mentioned on my previous post helped me.
This issue is solved.