Can you try by clearing the cache of the browser (in the system where you opened the vSphere client)?
PS: After clearing the cache, launch the vSphere client again.
Let me know, if that works.
What is the name of the customer?
Regarding the issue you are facing i.e. the service does not shutdown properly:
This is because the IMF feature was ON for the SQL Service monitoring agent of AppHA.
IMF feature helps an AppHA monitori...
This will be more involved (and complex) process then.
I would recommend opening a support case, so that support can help/guide you in the process.
Otherwise, follow these steps carefully:
1) Before changing IP of vCenter, un-register the plugin f...
Which IPs are being changed?
Is it only the vCenter server IP or the HA Console server IP or both?
If its just vCenter Server whose IP is being changed, then just doing plugin un-registration, followed by plugin registration with th...