Multiple syncs at exactly 62.675 Mb/s with a 9db+ SNRM sounds like a banded line.
Asking the ISP to run an RTT test will show the DLM line profile and confirm any banding.
A GEA test will show the line profile 13 days ago.
There may be an underlying line fault causing the line to be banded.
It could have been user initiated/self inflicted.
I've banded my own line in the past from swapping modems, upgrading firmware/constantly rebooting the modem.
Swapping between Broadcom and Lantiq chipset modems can even see the banding level change between each modem.
An example previously on the forum saw the Broadcom sync at 14,999, and Draytek (Lantiq) would sync at 11,399, with each modem always syncing at those figures when swapped. Both are banding figures used by OpenReach at the time.
The example I just mentioned.OpenReach have since increased the number of banding levels that they use considerably (was done around 2019 I think).
I've no idea if 62.7 is a banded figure, I can't keep up.