@Andrew Kroeger, Thanks for posting in Q&A. Based on my researching, for the custom notification sound format on Outlook for Android, it can be an audio file that is in one of the following formats: MP3, WAV, or OGG. But from your description, I notice we already tried these format.
For this issue, I notice the affected device is Samsung Galaxy. Could you check on other Android device to see if the same issue exists? And if we set the custom notification sound on Outlook on a device which is not enrolled into Intune, will we have the same issue?
If there's any update, feel free to let us know.
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