We recently deployed several 8851 and 8861 phones in our company, I noticed that the line button doesn't often gets highlighted when I push it. I have to push it hard enough and hold it momentarily to highlight it.
One of our department has phones with multiple lines for different services and they requested that "Always Use Prime Line" be set to "off". With this feature enabled, there is a need to push the line button before answering the call making it difficult for users to push line button several times and then press the answer button on the right to answer a call.
Is this a known issue? Did someone notice this? We are running sip88xx.11-0-1-11.
I don't see a bug or a field notice related to this. If the endpoints are already running one of the latest versions of firmware then its most likely a hardware or a 'user perception' issue. You may want to check with TAC if they can find anything in the phone debugs.