More data: it only "hangs" on some mail. Simple, single "To:" seem to work. Here is the original To/CC list (addresses are mangled to avoid spam) that would "hang":
| From: "MEYER,ALAN C. (HP-FtCollins,ex1)" <[EMAIL PROTECTED]> | To: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>, | "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>, | "HELGAAS,BJORN (HP-FtCollins,ex1)" <[EMAIL PROTECTED]>, | "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]> | Cc: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>, | "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>, | "GOBEILLE,BOB (HP-FtCollins,ex1)" <[EMAIL PROTECTED]>, | "KAO,PING-HUI (HP-FtCollins,unix1)" <[EMAIL PROTECTED]>, | "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]> grant Grant Grundler +1.408.447.7253