This is expected behavior and i don't think there is any way to change it as of now.
As sree mentioned No way we can restart the controller counting from #1.
I guess you can give a try, Unregistered the NSX Manager with vCenter Server Then reboot NSX Manager n try to register Manager with VC.
No this will not work, the controller is on a counter and that will continue to increment. At the end of the day it is just a number, we have controllers since the early days which have no names. There is no way i can find to remotely configure the names now they have been deployed and the only way is to delete and redeploy. You have a number issue and my controllers are referred to as 'null'
Count of the controllers are in NSX Manger database, there is field which increment count numbers. this is a good indication what was done to controllers before.
there is no practical reason why you want to change numbers. It just a number nothing more. DB is hidden from access and I not recommend you to play with it if you never touch NSX Manager DB
If you OK with answers , can you mark them please as helpful or correct to close the loop
thanks in advance