Strange build error editors/libreoffice on 11.0-RC2


I just got the following build fail from poudriere:
[build LNK] CppunitTest/
[build LNK] CppunitTest/
Abort trap (core dumped)
OK (1)
Fatal error 'mutex 0x8141ebb00 own 0x18e8c is on list 0x690064003a003a 0x74006e0065006e' at line 153 in file /usr/src/lib/libthr/thread/thr_mutex.c (errno = 0)

No core file identified in directory /wrkdirs/usr/ports/editors/libreoffice/work/libreoffice-
Any insight on this error message? Could this be a bug in the compiler and/or threading library?

poudriere is running in a jail on a so far otherwise idle machine with quadcore HT intel Xeon (8 builders) and 64GiB RAM ...

edit: Just a quick update, the problem proved irreproducible on a second bulk run, it now built just fine. Still I'd be interested to know what exactly this error message could have meant ;)