Cactiusers.org

I recently created an aggregate graph of two WAN links to a remote site, and I noticed that the inbound traffic display for the second link is not correct. In the graph templates for single links, I have inbound traffic above the y-axis and outbound traffic below the y-axis, and this works fine. I created a CDEF to make the outbound traffic negative to do this.
In this aggregate graph, the inbound traffic for the second link is not only not stacking, it's not showing up on the inbound side of the y-axis. There is also a small section on the graph where it looks like the inbound and outbound data on the second link show up on the wrong side of the y-axis.

The CDEFs appear to be correct, and the graph anomaly above (inbound data shows up on the wrong side of the axis) does not show up in the graphs for the individual interfaces.

The aggregate graph is using auto-scaling and is configured to ignore the upper and lower graph limits.

There are four elements total (traffic_in and traffic_out on each of the two links)

Any ideas what could be causing this and what I can do to fix it would be greatly appreciated.

This is under Cacti 0.8.7e, plugin arch 2.5, and aggregate plugin 0.71

Thanks in advance
jms