Pull Request not getting closed during merge

[Dileep Prasad]

Hello,

Here is my scenario

I create a Pull Request between 2 branches namely release and master.

I have a job which merges these two branches if there are no clonflicts.

Some times the Pull Request created between these branches gets closed automatically and sometimes not.

What is the defult behaviour here?How can I close all Pull Requests ( without manual intervention) once the merge between these two branches is successfull.

Thanks,

D.