We wrote a custom document ID provider to assign friendly number (1,2,3,etc.) to documents scoped at the farm level. All site collections use this provider, so no matter where the document is saved - it will receive the next number available. The values are tracked in a SQL database.
My problem is that the custom provider occasionally stops working. Both the DocID service and my custom provider are activated, but for some reason it will stop using my custom provider and revert to the default DocID like PX839912ASS. The fix is simply deactivating my custom provider, and then turning it back on.
Unfortunately this is really annoying, and I'm having a tough time figuring out why this is happening. It seems completely random at this point. Has anyone seen this behavior with custom providers?