A fixed version (2.6.5) is available in svn if you need. I will release a tarball next week.
I inserted a new debug msg into persist_dbm.c file and in some env it can generate some debug msgs because the level is 1.
If you set debug log in production and are seeing multiple msgs like:
You have an option to apply this patch sent by a user: https://www.modsecurity.org/tracker/browse/MODSEC-293, that change the level to 9.
It will be applied in the next version.