Impossible to tell what going on without a modem with advanced stats or an ISP provided profile.
DLM never moves from 6dB to 3dB though, ever, not even during the previous trials.
Even lines that develop serious errors go backwards in 1dB stages, not from 3dB to 6dB.
There are numerous things that can cause you to sync 3dB off the target though.
Edit:
here's a thread showing a line seemingly jumping between 6dB and 3dB.
Advanced stats (including max attainable and minute by minute detailed SNRM) was able to show the line only moved in 1dB increments.
ISP devices don't always poll the SNRM frequently.
The target would also be 3.3dB and not 3.0dB.
it could be a 3.3dB intermittent noise source that isn't enough to effect the sync but is shown in the current SNRM.
A previous crosstalkers with a faulty line can cause this kind of thing.
It could actually be a 3dB SNRM target but history has shown in these forums dozens of examples that looked to be 3dB that weren't, including lines that resync at 3dB.
On the successful Huawei G.INP trial they didn't try xdB profiles.
On the xbB trial the DLM moved in 1dB increments.
I can't see why they would try straight to 3dB on a failing G.INP trial without even trying 5dB.
I'm of the opinion it isn't a 3dB target. Seen this SO many times before.
