[syslog-ng]Linux boxes periodically stop logging?

I apologize for the lack of technical detail in this post, but, for the moment I'm just trying to ascertain if I or my syslog-ng config are on drugs. Basically, I have a mixed array of Linux (RedHat 6.2 & 7) and FreeBSD (4.2-S) machines on which I'm running syslog-ng and logging to a central host. (FreeBSD 4.2-S) The problem is that the Linux boxes periodically stop logging. If I send the daemon a HUP, it comes back to life and data starts flowing again, but any log messages that would have appeared while the daemon was hosed are gone. Has anyone experienced anything like this before? Thanks in advance, -Snow