Hi,
Sounds like this defect: CSCsd95898.
I copied/pasted the defect's release note enclosure below. Kind of a gray area as far as by design -- more likely an unintentional side effect of soft deletions. But the defect has been closed and won't be fixed.
Nancy
Symptom:
When you leave a voice message via the TUI, a copy of that message could be left in the user's Trash folder.
Conditions:
Cisco Unity 4.0(5) and earlier running with DUCS 1.2.2 and DUCS 1.2.3 and Lotus Domino and Notes 6.x
Lotus Domino 6.x introduced the concept of 'Soft Deletions'. When the 'Soft Deletions' option is enabled a copy of that message is placed in the Trash folder for XX number of hours before being permanently deleted.
Workaround:
None within Cisco Unity at this time but within Lotus Domino you can do one of the following:
1) Disable Soft Deletions
2) Leave the Soft Deletion option enabled and let it delete the messages from the Trash folder permanently when "Soft Delete expire time in hours" expires. Refer to "Soft Delete" under Lotus Domino help file for details on how to configure the 'Soft Delete' option.