Planning console shows sys_id instead of showing user name for ‘Assigned to’ field
There are corrupted live profile records for the user
After deleting the corrupted duplicate record under live_profile table for the user resolves the issue
There is ‘name’ field under live_profile table, make sure user should not have sys_id mentioned under ‘name’ field. If you find those corrupted record, please replace the sys_id with user name and retest the issue. It should be fine.