oak-run compact makes repository grow

Dear Experts,

currently I observe a strange behavior on one of our AEM 6.2 (all updates installed) publish instances. Every time I run oak-run compact, repository gets bigger, instead of smaller. There are no errors and some tar files are really removed and added like here:

size 115.7 GB (115699274801 bytes) removed files [data01280a.tar, data01429a.tar, data01389a.tar, data01564a.tar, data01393a.tar, data01235a.tar, data01410a.tar, data01456a.tar, data01293a.tar, data01375a.tar, data01579a.tar, data01574a.tar, data01326a.tar, data01289a.tar, data01547a.tar, data01385a.tar, data00312h.tar, data01445a.tar, data01327a.tar, data01588a.tar, data01577a.tar, data01332a.tar, data01485a.tar, data01217b.tar, data01495a.tar, data01339a.tar, data01420a.tar] added files [data01332b.tar, .nfsE86D61, data01485b.tar, .nfs496D61, .nfsA76D61, data01547b.tar, data01375b.tar, .nfs986D61, data01393b.tar, data01327b.tar, .nfs296D61, data01579b.tar, .nfs186D61, data01385b.tar, data01389b.tar, data01326b.tar, .nfsB76D61, data01445b.tar, data01339b.tar, data01293b.tar, data01588b.tar, .nfs686D61, .nfs586D61, data01217c.tar, data01410b.tar, .nfsC76D61, data01574b.tar, .nfs786D61, .nfsE76D61, .nfs386D61, data01495b.tar, data01456b.tar, data01280b.tar, data01577b.tar, .nfs286D61, data01564b.tar, .nfs096D61, .nfsC86D61, .nfsF76D61, .nfs086D61, .nfs486D61, .nfsA86D61, data01289b.tar, .nfs396D61, data00312i.tar, .nfsF86D61, data01429b.tar, .nfsD86D61, .nfsD76D61, .nfs886D61, .nfsB86D61, .nfs196D61, data01420b.tar, data01235b.tar] Compaction succeeded in 8.109 min (486s).

But each time the "compaction" adds about 3GB of extra volume. On other publishers the repository size after compaction is about 10GB, so I am already 10 times over normal size

What can be done to remediate this issue?

Kind regards,
Ivan