gcache.page files are not deleted

Hello all,

we are using MariaDB-Galera-Cluster 10.0.12 and we ran (again) into the problem that lots of gcache.page-files are created but not deleted.
I'am wondering why we have gcache.page-files at all because we set gcache.size to 50G! However, this problem eats up all disk space within a few days.

Node 1:

1. ls -lh gcache*
   rw------ 1 mysql mysql 256M Sep 24 08:00 gcache.page.000080

Node 2:

1. ls -lh gcache*
   rw------ 1 mysql mysql 256M Sep 21 12:22 gcache.page.000000
   rw------ 1 mysql mysql 256M Sep 21 13:25 gcache.page.000001
   rw------ 1 mysql mysql 256M Sep 21 14:39 gcache.page.000002
   rw------ 1 mysql mysql 256M Sep 21 15:55 gcache.page.000003
   rw------ 1 mysql mysql 256M Sep 21 16:59 gcache.page.000004
   rw------ 1 mysql mysql 256M Sep 21 18:03 gcache.page.000005
   rw------ 1 mysql mysql 256M Sep 21 19:07 gcache.page.000006
   rw------ 1 mysql mysql 256M Sep 21 20:03 gcache.page.000007
   rw------ 1 mysql mysql 256M Sep 21 21:01 gcache.page.000008
   rw------ 1 mysql mysql 256M Sep 21 22:04 gcache.page.000009
   rw------ 1 mysql mysql 256M Sep 21 23:23 gcache.page.000010
   rw------ 1 mysql mysql 256M Sep 22 00:43 gcache.page.000011
   rw------ 1 mysql mysql 256M Sep 22 02:22 gcache.page.000012
   rw------ 1 mysql mysql 256M Sep 22 04:19 gcache.page.000013
   rw------ 1 mysql mysql 256M Sep 22 06:14 gcache.page.000014
   rw------ 1 mysql mysql 256M Sep 22 07:29 gcache.page.000015
   rw------ 1 mysql mysql 256M Sep 22 08:44 gcache.page.000016
   rw------ 1 mysql mysql 256M Sep 22 09:55 gcache.page.000017
   rw------ 1 mysql mysql 256M Sep 22 10:56 gcache.page.000018
   rw------ 1 mysql mysql 256M Sep 22 11:57 gcache.page.000019
   rw------ 1 mysql mysql 256M Sep 22 12:54 gcache.page.000020
   rw------ 1 mysql mysql 256M Sep 22 13:56 gcache.page.000021
   rw------ 1 mysql mysql 256M Sep 22 14:59 gcache.page.000022
   rw------ 1 mysql mysql 256M Sep 22 16:02 gcache.page.000023
   rw------ 1 mysql mysql 256M Sep 22 17:07 gcache.page.000024
   rw------ 1 mysql mysql 256M Sep 22 18:04 gcache.page.000025
   rw------ 1 mysql mysql 256M Sep 22 19:15 gcache.page.000026
   rw------ 1 mysql mysql 256M Sep 22 20:26 gcache.page.000027
   rw------ 1 mysql mysql 256M Sep 22 21:36 gcache.page.000028
   rw------ 1 mysql mysql 256M Sep 22 22:51 gcache.page.000029
   rw------ 1 mysql mysql 256M Sep 23 00:38 gcache.page.000030
   rw------ 1 mysql mysql 256M Sep 23 02:32 gcache.page.000031
   rw------ 1 mysql mysql 256M Sep 23 04:54 gcache.page.000032
   rw------ 1 mysql mysql 256M Sep 23 06:52 gcache.page.000033
   rw------ 1 mysql mysql 256M Sep 23 08:00 gcache.page.000034
   rw------ 1 mysql mysql 256M Sep 23 09:14 gcache.page.000035
   rw------ 1 mysql mysql 256M Sep 23 10:19 gcache.page.000036
   rw------ 1 mysql mysql 256M Sep 23 11:29 gcache.page.000037
   rw------ 1 mysql mysql 256M Sep 23 12:34 gcache.page.000038
   rw------ 1 mysql mysql 256M Sep 23 13:43 gcache.page.000039
   rw------ 1 mysql mysql 256M Sep 23 14:48 gcache.page.000040
   rw------ 1 mysql mysql 256M Sep 23 15:49 gcache.page.000041
   rw------ 1 mysql mysql 256M Sep 23 16:53 gcache.page.000042
   rw------ 1 mysql mysql 256M Sep 23 17:56 gcache.page.000043
   rw------ 1 mysql mysql 256M Sep 23 19:04 gcache.page.000044
   rw------ 1 mysql mysql 256M Sep 23 20:08 gcache.page.000045
   rw------ 1 mysql mysql 256M Sep 23 21:11 gcache.page.000046
   rw------ 1 mysql mysql 256M Sep 23 22:26 gcache.page.000047
   rw------ 1 mysql mysql 256M Sep 23 23:30 gcache.page.000048
   rw------ 1 mysql mysql 256M Sep 24 00:53 gcache.page.000049
   rw------ 1 mysql mysql 256M Sep 24 02:34 gcache.page.000050
   rw------ 1 mysql mysql 256M Sep 24 04:29 gcache.page.000051
   rw------ 1 mysql mysql 256M Sep 24 06:14 gcache.page.000052
   rw------ 1 mysql mysql 256M Sep 24 07:28 gcache.page.000053
   rw------ 1 mysql mysql 256M Sep 24 07:57 gcache.page.000054

Node 3:

1. ls -ls gcache*
   262148 rw------ 1 mysql mysql 256M Sep 24 01:29 gcache.page.000000
   262120 rw------ 1 mysql mysql 256M Sep 24 03:22 gcache.page.000001
   262148 rw------ 1 mysql mysql 256M Sep 24 05:14 gcache.page.000002
   262148 rw------ 1 mysql mysql 256M Sep 24 06:49 gcache.page.000003
   262148 rw------ 1 mysql mysql 256M Sep 24 07:53 gcache.page.000004
   262148 rw------ 1 mysql mysql 256M Sep 24 08:01 gcache.page.000005

So all this started suddenly on Sep 21. We haven't changed anything that day and you can't find something unusual in the error logs. (attached)
This happend one time before, we "fixed" the problem by stopping the servers successively and deleting the gcache.page-files physically. This worked for about two weeks and now the problem ist back.
Even more confusing: In contrast to Node 2 and 3, Node 1 creates the gcache.page-files (whatever the reason is) and deletes it again after filling it up..

All this happens even due to very low load times (at night).

I also attatched the my.cnf we use.
I reported this problem at codership too but i haven't received a response until now. (https://groups.google.com/forum/?hl=de#!topic/codership-team/1OKXmpzfmwc)

I would be very thankful for any help regarding this issue.

Thank you and best wishes
Philipp