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. 

From the following documentation we see that this is the default behavior : 

https://developer.atlassian.com/platform/forge/events-reference/jira/?tabId=4&tab=payload#issue-assigned

Issue assigned
An event with the name avi:jira:assigned:issue is sent when a user is assigned or unassigned from an issue. An "issue updated" event will also be sent when this occurs.