I'm currently running the network edition of 5.0.1

I've recently noticed that sometimes the scheduled full backup reports success but doesn't seem to back up properly:

Label: full-20080409.150135.256
Type: full
Status: completed
Started: Thu, 2008/04/10 01:01:35.256 EST
Ended: Thu, 2008/04/10 01:01:51.859 EST
Redo log sequence range: 133 .. 133
Number of accounts: 1

The output of a successful full backup looks like this:

Label: full-20080404.150014.043
Type: full
Status: completed
Started: Sat, 2008/04/05 01:00:14.089 EST
Ended: Sat, 2008/04/05 01:33:57.708 EST
Redo log sequence range: 126 .. 126
Number of accounts: 52

Note the "Number of accounts: 1" instead of the expected 52. The size of the backup as reported by a "du" command is also around 500KB for the broken ones instead of the usual ~30GB of the other full backups. The backup process also takes around 15 seconds instead of an expected 30 minutes.

Incremental backups on the other hand always seem to work fine.

The disk is nowhere near full so that can't be an issue.

The backup system is not something you want to be flakey! Are error conditions reported correctly by the backup system?

Any ideas?