In Confluence Cloud at page edit mode macros typically are rendered in a modern style. For SharePoint Connector for Confluence macros the modern style includes a preview of the embedded SharePoint document respectively list:
Image 1: Modern Style Macro Preview in Page Edit Mode (click to enlarge)
For migrated pages, however, the macros are rendered in the "classic style" (like they are at Confluence Server respectively Data Center):
Image 2: Classic Style Macro in Page Edit Mode for a Migrated Page (click to enlarge)
This applies not only to migrated macro instances but also to newly added ones.
Fallbacks for not yet Supported Features
At current not all features of SharePoint Connector for Confluence available in the Server respectively Data Center version are supported in the Cloud version, too. For the already supported features see User's Guide (Cloud).
Document Macro: Display Option "Responsive View"
For a migrated page, if in the original page the Display Option "Fixed View" or "Responsive View" was configured for a macro then in the migrated page the configured Display Option will be "Embed".