When you attach a file to an email from OneDrive, you may notice that the file is attached as a cloud attachment by default and not a local copy.
The setting for OneDrive files to be shared as cloud attachments by default has now been rolled back. In order for the change to take effect, please restart Outlook 2016, and you should go back to the original experience of seeing both a local copy of your OneDrive file in the Attachments menu, in addition to the cloud link, allowing you to select how you prefer sending your OneDrive file.
OneDrive cloud attachments are there to promote collaboration by allowing you to share a single version of the document, automatically permissioned to your recipients without going to OneDrive. In general, if you want to send a copy of the cloud file instead, you can select Attach as copy from the attachment menu. This option has always been available to you to choose.
We do appreciate the feedback and are invested in improving the overall experience of sharing OneDrive files. Expect to see further flexibility around setting default settings for OneDrive sharing in the upcoming year.