0.8.7c: Vanishing I/F Traffic template / Database corruption

[cfour]

I've encountered this problem a couple of times now, though I haven't quite figured out what brings it on: The 'Interface - Traffic' template vanishes, preventing creation of any further traffic graphs. More correctly, it looks like something is causing spurious database corruption as to prevent the facility from working.

I've observed that item 41 is missing from the 'data_template' table, that is the ID for this particular template. Even after inserting the missing row, it doesn't show up in the list of templates. Even after re-creating any template(s) copied from an adjacent host, this one still will not create the RRDs/data sources/graphs for interfaces.

Curiously, I can create graphs for error rates, but not traffic rates. Can someone shed some light on where else to look in the DB?