Got modem back on after three hours powered down.
The ES and SES has suddenly stopped now and downstream SNR are spot on now.
As mentioned earlier by b*cat when the SNRM starts oscillating like the way it was, then powering down for a while can often resolve this.
I know this isn't the first time and I have definitely told you at least once in the past, possibly more when I've seen your line do similar. Powering down for a short while resolved it in previously for you.
It usually occurs after an enforced remote power down OR power cut/power surge. When the modem comes back up the SNR starts spiking in the behaviour displayed on your graphs.
It's not unique to your line - I've seen it happen on many other lines. It's not unique to the modem or FTTC either.
Mine has been doing so way back to the days of maxdsl. The first time I saw it happen was using a Voyager 2100 after a workman turned power off at the mains. I was monitoring using MRTG (there was no Routerstats back then nevermind DSLstas).