I've had a solid 79995 / 20000 sync on my line for the last year, with no disconnects / reboots in about 2 months. This morning at around 6.30 my Draytek 2860 reported a disconnect / reconnect, and now I'm connected at 74728 / 20000 with an Interleaving depth of 1089! This seems very odd to me - as I understood it, interleaving would only be applied on a line with clear instability, which mine definitely doesn't have. I have tried a reboot in the meanwhile but nothing has changed.
Any idea what may have happened here, and moreso how I could report this issue to BT (my ISP) without getting fobbed-off? I'm less bothered about the 5Mbit drop but really don't want the unnecessary Interleaving. My attainable rate is showing as 86475 which is even stranger. If it was during working hours I'd have thought someone made a manual error but this confuses me.
Thanks in advance!