In Outlook for Mac (New Client), sending an email sometimes takes an unusually long time when New Editor Preview Mode is enabled and the Undo Send option is set to 10 seconds. After clicking Send, the email delivery can take more than 40 seconds to complete, resulting in a noticeable and inconsistent delay compared to expected behavior.

Steps to reproduce

1. Open Outlook for Mac (New Client).
2. Enable New Editor Preview Mode.
3. Enable Undo Send and set the delay to 10 seconds.
4. Compose a new email and click Send.
5. Observe the time taken for the email to be delivered.

Link to live example(s)

1. Undo Set to 10 Seconds new editor Disabled
2. Undo set to 10 Seconds new editor Enabled

Provide additional details

1. With New Editor Preview Mode disabled and Undo Send set to 10 seconds, emails are sometimes delivered within 17–20 seconds, but in some cases still take 35–40 seconds.
2. When Undo Send is completely disabled, emails are sent almost instantaneously (2–3 seconds), regardless of whether the New Editor Preview Mode is enabled.
3. The issue is only reproducible when Undo Send is enabled (10 seconds), suggesting a potential interaction between Undo Send and the New Editor experience.
4. We have noticed that sometimes the task pane also remained open after the send button is clicked, which can be seen in the second video in the live examples section.

Context

This behavior impacts end-user productivity and creates uncertainty around email delivery timing. Users expect a consistent send experience, but the extended delay (up to 40+ seconds) causes confusion and may lead to duplicate sends or repeated attempts. We are trying to understand whether this is a known limitation or a defect related to the New Editor Preview Mode and Undo Send interaction in Outlook for Mac.

Useful logs

• Raised the Incident through collect Diagnostics in Outlook, Incident ID :- ZQQERCE3

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