Sometimes combinations of store messages, how the call is transferred to the voicemail and when you have VMID as 990 can cause unpredictable behaviors . I was told by a former Toshiba guru at my company to use a VMID that does not correspond with an actual mailbox. Then the main greeting will always play correctly (assuming that you have store messages box unchecked). Mail Box 990 is default. It will play when Stratagy does not have a better place to send the caller.

I can see that the voicemail picked up the call as if it was Ring no Answer for user 990 and tried to record a message. The second time the greeting played was as an automated attendant.

You are correct about the log files in the PBX. They are only useful to Toshiba support.