Hello all.

Sorry for the delay. The project was on hold for some time and after that I forgot to add the answer here. After a ticket with ServiceNow, we found that the problem was as follows: 

The main issue was that under the 'Contain Roles' related table, inside the ‘sn_devops.viewer’ and the ‘sn_devops.tool_owner’ roles records, there was a role named '(empty)' (the SN employee also told as that it could also be named 'sn_change_read is listed'). After we removed it, and checked that the sys id was not in the XML file, the issue was solved.