ibus-engine-mozc assert failure: *** buffer overflow detected ***: /usr/lib/ibus-mozc/ibus-engine-mozc terminated

not sure how to reproduce this, but it happended several times.

ProblemType: Crash
DistroRelease: Ubuntu 15.04
Package: ibus-mozc 1.15.1857.102-1build1
ProcVersionSignature: Ubuntu 3.19.0-9.9-generic 3.19.1
Uname: Linux 3.19.0-9-generic x86_64
ApportVersion: 2.16.2-0ubuntu4
Architecture: amd64
AssertionMessage: *** buffer overflow detected ***: /usr/lib/ibus-mozc/ibus-engine-mozc terminated
CurrentDesktop: Unity
Date: Mon Mar 23 01:23:02 2015
EcryptfsInUse: Yes
ExecutablePath: /usr/lib/ibus-mozc/ibus-engine-mozc
InstallationDate: Installed on 2015-02-28 (22 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Alpha amd64 (20150228)
ProcCmdline: /usr/lib/ibus-mozc/ibus-engine-mozc --ibus
Signal: 6
SourcePackage: mozc
StacktraceTop:
 __libc_message (do_abort=do_abort@entry=2, fmt=fmt@entry=0x7f3d38c06dad "*** %s ***: %s terminated\n") at ../sysdeps/posix/libc_fatal.c:175
 __GI___fortify_fail (msg=<optimized out>, msg@entry=0x7f3d38c06d44 "buffer overflow detected") at fortify_fail.c:38
 __GI___chk_fail () at chk_fail.c:28
 __fdelt_chk (d=<optimized out>) at fdelt_chk.c:25
 ?? ()
Title: ibus-engine-mozc assert failure: *** buffer overflow detected ***: /usr/lib/ibus-mozc/ibus-engine-mozc terminated
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip docker libvirtd lpadmin plugdev sambashare sudo