Why Blocker and Highest Priority changing automatically to High Priority post creating issue?

[Venkateswararao Karanam]

I am Jira admin. I have created few issues with Priorities as Blocker and Highest. But Immediately it is changing to High priority. Again i am going inside the issue, i am able to change the priority to Blocker or Highest. 

This is happening for normal users also.

What changes should I perform to resolve the issue?

Note: This is happening for the most of the existing projects and for one project it is not happening.

[Ash Yadav]

Hi @Venkateswararao Karanam , 

Do you have any global automation rules enabled perhaps? 

KR, 

Ash