I think this is related to a known issue. Something similar happens when you edit OBS on project. Refer to the below -
Defect No. CLRT-74259
Title: Audit fields Changed By and Date Timestamp for OBS incorrect
Steps to Reproduce:
1. Go to Admin Tool --> Resources
2. Create 2 new resources and add admin access rights to both
3. Go to Admin Tool -> Objects -> Project -> Audit Trail
4. Set up Attribute Audit for Department OBS
5. Login as Resource 1, navigate to a project and update the Department OBS
value
6. Check the Audit Trail tab for the Project. For the first time the
attribute is changed, the audit trail shows all the values (Attribute Name,
Operation, Changed By, Old Value, New Value and Date) correctly
7. Now logout as the Resource 1 and login as Resource 2
8. Navigate to the same project in Step 5 and update the Department OBS
value
9. Check the Audit Trail tab for the Project. The 'Changed By' shows
incorrectly as Resource 1 and 'Date' shows incorrectly as the Date and
Timestamp of Previous Update.
Expected Result: The Changed By and Date Timestamp should show the values
from the second update
Actual Result: The Changed By and Date Timestamp shows the values from the
first update