gprint weirdness

[foxbert]

I am using cacti to graph active connections on USR total control racks. From the rra's and the graphs I can tell the data extraction is going ok
However I have come across a very weird thing, sometimes the graph does not seem to pick up the GPRINTs I've defined.

Sometimes we get something like this :

/usr/local/rrdtool/bin/rrdtool graph - \
--imgformat=PNG \
--start="-86400" \
--title="Netsrv00 Active Calls" \
--base=1000 \
--height=120 \
--width=500 \
--alt-autoscale-max \
--vertical-label="" \
DEF:a="/mon/cacti/rra/netsrv00_modem_usage.rrd":netsrv00_modem_usag:AVERAGE \
AREA:a#0000FF:"" \
LINE1:a#000000:"" \
GPRINTMAX:"maximum calls\:%8.0lf\n" \
GPRINTAVERAGE:"average calls\:%8.0lf\n" \
GPRINTLAST:"current calls\:%8.0lf"

(which is correct) but other times we get this :

/usr/local/rrdtool/bin/rrdtool graph - \
--imgformat=PNG \
--start="-86400" \
--title="Netsrv05 Active Calls" \
--base=1000 \
--height=120 \
--width=500 \
--alt-autoscale-max \
--vertical-label="" \
DEF:a="/mon/cacti/rra/netsrv05_modem_usag.rrd":netsrv05_modem_usag:AVERAGE \
AREA:a#0000FF:"" \
LINE1:a#000000:"" \
\
\

(which I got from duplicating the previous item!) This is obviously not so correct considering I do have GPRINTs defined on this. Even a quick look in mysql confirms this.

I have to say that this is rapidly doing my head in, and I would great appreciate any help given!