I'm sure all concerned are doing their best, but why is it taking so long to fix? (Rhetorical question really, I know how difficult intermittent problems and those that don't effect everyone are to trace and fix). This has been going on now for over six weeks, and the same notice as below was posted on 14th December 2005.
I know it's affecting the LJ team as well, but....
Posted by: admin
We have recognized an issue that is preventing some outgoing email from being delivered on time. The fix for this problem is not immediate, however, so we cannot promise a speedy resolution to this issue. In the meantime, you may receive comment notifications, payment receipts, rename tokens, and other mail from LiveJournal later than expected as the backlog of undelivered mail clears.
We're really very sorry about the continued delays with this feature. There is no longer a need to open a support request providing links to missing comments; we have sufficient information to continue investigation.