Undocumented EventID in the message tacking logs: HAREDIRECTFAIL

Hello,

I am seeing many results from running Get-MessageTrackingLog that have an EventID of HAREDIRECTFAIL.  A quick search of Google and Bing indicates zero info.

Does anyone know what this means, or has any seen it before?

The mail flow seems to be working OK, but I checked the logs when a user complained of a missing email.  I'm not necessarily convinced that the HAREDIRECTFAIL is related to that issue, as many messages have this status, and I know they succeeded.

Thanks!