After publishing a packaged i-Model, we occasionally find that some of the reference attachments from the original DGN file are missing in the corresponding i-Model.
If the reference attachments used in the DGN source file are stored in a location such as OneDrive, it's possible that connection issues could be inadvertently affecting the reference file paths, causing those same references to be missing within the packaged I-Model. If possible, try copying all files to a local hard drive or a network drive with known stable bandwidth and try republishing the i-Model from there.