due to a fault from Cisco licensing we had to install activation key several times. all feature are the same, only the number or Anyconnect Premium peer was different in the keys.
But with every activation key installation clients report VPN problems and this was because the ASA activated the Essentials itself.
Somebody has seen this. Is this normal behavior?
I've installed numerous activation keys and have never encountered this behavior.
I would only expect Essentials to be active if you had it licensed and used the "anyconnect essentials" command in the config.
We had a wrong 500 Anyconnect Premium peers license instead of 1000. Customer though this will be added to the active 1000 peers. He installed the 500 and disabled the essentials after he has seen the issue.
He installed the 1000 peers activation key again and had to disable essential again. The configuration was always saved.
No we have the proper 1500 peers activation key and it happened again after the installation.
As you noted, Premium license are not additive - you need to purchase an upgrade license to get the number of clients increased.
That is certainly odd because it seems as if you are following the correct path now. It sounds like something is wrong with the key.
I'd open a TAC case and request escalation to get it resolved. You may need to get the licensing team to talk to the engineering support side - that can be a challenge as they tend to just hand you off.