I am not abscent. I am following this thread and reading all contributions.
Its not only a matter of Self Calibration. It probably will fix this issue, as I agreed before in this topic.
The problem is that Keysight is refusing the warranty, and as Daniel said above Keysight expect 6 months of stock, never 8 years as is my case.
So I bought the scope as brand new expecting full warranty (and this expectation is supported by Brazilian law), and it is not what I got.
If tomorrow the scope presents a more serious problem, I will need the warranty.
Today Nortron answered my email, asking to wait that my problem was escalated inside Nortron.
I will just ignore some comments saying that I want a new scope, free scope, free services, etc, it is not worth the time to reply, sorry.