I am running into an issue using the 'Office 365 Upload File'. I am able to successfully upload a file (and update some fields) to a document library from a list attachment. However, I run into errors when updating a field that has multiple users in it. 

On the list item, I have a field (person/group column) that allows for multiple selections. When only one person is entered, it works fine. The issue arrises when there are multiple people selected. In my 'Office 365 Upload File' workflow action I am using the "User Ids, Semicolon Delemited" format when selecting the field as the value. 

My question is: Is the 'Office 365 Upload File'  workflow action only capable of updating a document library's "Person/Group Column" with one user and not multiple?

Any help would be greatly appreciated!