Currently, updating the assignee field on an issue triggers an 'Issue Updated' event, which may activate unnecessary hooks. Since there is already an 'issue_assigned' event, it would be better to keep just the 'issue_assigned' event or the 'issue_updated' event, similar to how it was in Jira 9 and earlier. 

Example: 

First Payload : 

{
  "timestamp": 1762780415913,
  "webhookEvent": "jira:issue_updated",
  "issue_event_type_name": "issue_assigned",

Second Payload: 
 

{
  "timestamp": 1762780415913,
  "webhookEvent": "jira:issue_updated",
  "issue_event_type_name": "issue_updated",
  "user": { 

In Jira 9 and earlier, only the issue_updated event is triggered, not the issue_assigned.