Another quirk today. After a month of the -1990 error message, I was able to book a domestic AS OW ticket from PDX-SNA. That went through two weeks ago. Today I went to cancel it because a cash fare with the companion certificate made more sense as an open-jaw RT. Went to cancel and the site gave me an error and I called in. 40 minutes on hold as they tried to figure it out. And we discovered the ticket never deducted the miles from my account. It in fact did not as I've been watching my balance like a hawk. The certificate was gone but not the miles after the book. On cancelling the certificate was immediately re-issued and no change in miles.