Adding a bump so that this isnt missed

Seems like a similar issue experienced within ticket 2C6-2260CEC5-000F 

Hello Jade, thanks for keeping this up there. We are investigating these issues further and hope to have feedback from development by the end of the week. I can confirm this does not affect all environments, and so it may take some time to get to the bottom of this, but its on our radar!

Jade, just a quick follow up here to keep anyone else watching up to date as well. We are seeing some intermittent issues on migration/retrieval, and are working to implement some additional diagnostic logging in these areas that should help us narrow down the root cause. 

So, if you're seeing issues with mailbox migration and/or IMAP/POP based retrieval, please submit a support ticket so we can get the logging build out to you once we have it available so we can narrow down and resolve these issues as soon as possible. 

I will follow up here again when we have resolution.

Thanks for the update Kyle

what was the result or end determination /fix for this?

Getting ready to migrate to SM15x to SM17 .. so becoming more interested in non-resolved issues

Migration issues have been resolved at this point (the ones that had been reported and tested) and should be in much better overall shape. If you do happen to run into issues please reach out to support so we can help work through them or get any bugs reported to development. Thanks!