Symptoms

User task error when querying smartobject
 

Diagnoses

List containing multiple people/group type columns. There are 13 custom columns. Generates error upon using Smo property for user task. XML_ErrorParsingEntityName did some troubleshooting by creating a separate list with 13 columns which worked without error. Found by renaming column name to special symbol (&) was the cause of the error. It would appear that SharePoint online does support special characters as part of naming columns in a list, but in K2 Appit it throws an error when tring to call the smartobject. 
 

Resolution

Verified this being a K2 product bug in the Create Reference Event wizard to be addressed in a future release of K2. Current workaround is to remove the & from the column name.