Keeping an eye on my RouterStats, sampling every 5sec.I note that at times the noise margin drops from between 19 to 22 db to zero and up again. Looking at the log it only registers once in 5sec. The sync rate (1888kbps) does not show a change. I do however see that the WAN up time has started counting again but the LAN up time is not affected. Will this event be seen as an error at the BT exchange and re zero any time to improvement? I'm using a cable connected Netgear 384G v5 and I see this effect in the test socket as well as on my extension.
I'm guessing you're resyncing at the same speed if the router has zeroed the WAN time. LAN time refers, effectively, to the interval between reboots. So, the short answer is that if you're waiting for a profile change, I think you are being sabotaged. :(
I agree, it looks to me like a resync if wan resets to zero, if you've got that much noise variation it's not got much chance of improving.