RealTime Workflos "The user who made changes to the record" Not Function CRM 2016

Hi Guys,

I have some issue regarding real-time workflow.

This happened when "Record is assigned" then update certain field in the same entity using real-time workflow.

After real-time workflow updated the field, entity "modified by" become SYSTEM who are not admin or any user that i had created.

After few round testing, i found that this only occurred in Account and Contact entity and also during assigned record to user follow by update using real-time workflow.

Please guide me on troubleshooting this issue. Thank You