Netgear CM3000 CMTS Provisioning Issue

First off, I've spent over 3 weeks troubleshooting this issue, to include over 7 hours yesterday.  4 hours straight of which I was transferred to Twelve (12) different agents due to their chat software glitching and disconnecting them from me.  Thus I had to repeat my issues TWELVE times!!  Only for them to disconnect and connect me with another agent and start all over!!  Icing on the cake?... the 10th agent had so much pity, before helping me, they asked if the previous 9 tried to sell me mobile services yet...??  Are you kidding me?!  Twelve agents folks is UNSAT!  Just to wake up to a mysterious technician appt this morning I DID NOT ask for that was going to charge me $100. (I told them I already had a tech visit...)

Background/Issue:  Upgraded internet to 1.2 Gbps last October and purchased a Netgear CM3000 to handle the speeds, as my previous CM1100 is only rated to like 866 Mbps.  It took a couple provisionings, but worked fine until the beginning of June.  My speeds kept dropping to 30 Mbps, lots of connection drops, lag, packet loss, you name it.  Reboot, speeds back up to 1+ Gbps, then 5 to 10 minutes later... throttled to 30 Mbps.  Contact support agent, re-provision, power cycle, speeds back to 1+ Gbps, then again, 5 minutes later... throttled to 30 Mbps.

Steps taken:

1.  Contacted tech support chat agents multiple times, re-provisioned multiple times.  Same issue.  They even were so kind to upgrade my speed to 1.3 Gbps (that I can't take advantage of currently...)

2.  Scheduled a technician visit.  He determined all interior cables and exterior attenuators were good, signal quality met my now 1.3 Gbps throughput, but the buried line to the street was degraded, not meeting the 2.1 Gbps expected rating.  And thus probably causing the connection drops (modem reacquiring signals throughout the day) and signal quality issues.  So he scheduled a buried line replacement, which is in progress.  Utilities have marked the ground, but digging hasn't been scheduled yet.  However, I should still be able to get 1.3 Gbps speeds with the occasional re-acq drop outs.  Power levels and SNR are all within spec, actually pretty good, even with the buried line degradation issues.  I definitely determined that assigning a lower  downstream channel lock, and thus lower frequency helps right now with PWR/SNR.  The cable is degrading higher freqs; I think the underground pipe may be PVC, crushed/broke, and penetrated or damaged the coax shielding.

3.  Since I kept dropping to 30 Mbps, we determined my CM3000 may be failing.  My spouse works from home and needed the bandwidth, so I re-connected my CM1100 and had it re-provisioned.  I then initiated an RMA/troubleshooting with Netgear for the CM3000.

4.  The CM1100 works, does not get throttled down to 30 Mbps, but does suffer from the buried line signal quality issues.  But it gets us by until the RMA process went through, even though it's not rated for the 1.3 Gbps.

5.  Received the replacement CM3000 modem yesterday, removed the CM1100, and had the CM3000 added to my account/provisioned.  Again 7+ hours of efforts, including over 4 fruitless hours in chat.  Showed "Status Unavailable" in account.  But Agents could see it initially after provisioning ("evertything looks good on our end"), speeds would hit 1+ Gbps, but again, after 5 minutes or so, it dropped to 30 Mbps.... And the Agents couldn't see it anymore.  Same issue with a replacement modem!!  Chat Agents would make me power cycle... and want to call it good.  Of course it would work in the first 5 minutes... then get throttled back down to 30 Mbps after receiving the following modem Event Log entry:

DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;

EVERY time that specific Warning is received, my CM3000 gets throttled down to 30 Mbps by the CMTS.

Preceding Log entries after a power cycle are as follows:

(Warning (5)) Dynamic Range Window violation
(Warning (5)) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
(Warning (5)) REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
(Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
(Notice (6)) TLV-11 - unrecognized OID;CM-MAC=redacted;CMTS-MAC=redacted;CM-QOS=1.1;CM-VER=3.1;
(Notice (6)) Honoring MDD; IP provisioning mode = IPv6
(Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=redacted;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
(Critical (3)) Resetting the cable modem due to docsDevResetNow

I get it... Chat agents have limited capability, and MUST use their script... every time... even if I have been disconnected from them 12 times!  However, NONE of them know what a CMTS is, or what firmware my CM3000 should be on, or help document/diagnose this throttling issue.  And they keep trying to sell me mobile services and/or the XB8 while waiting for power cycles.

My CM3000 Firmware:  V5.01.02 (worked from Oct 2024 to June 1st 2025...)  Have seen there is a V6.01.03 out there as of 6/16/2025, but it is causing issues, so folks have asked to roll back to V5.01.02!  I am wondering if the Seattle area CMTS is trying to push/provision my CM3000 with V6 firmware, and the process isn't working, or the CMTS thinks I'm on V6, when in fact it's still V5.  I don't know, but the CMTS keeps throttling my CM3000 within 5 to 10 minutes after provisioning or power cycling / reboot!  CM3000 is on the allowed equipment list, and one of the few that can handle 1.3+ Gbps.

So for now, I re-added the CM1100 and that's what I'm using until this gets resolved.  I don't want the XB8, because I already have a WiFi 7 router and home network I built.  I know it can be put into "Bridge Mode" and disable the wifi radios, but heard it still transmits a hidden wifi channel for the event of a technician visit needing to connect to it.  My modem sits next to my router, so I wouldn't want the hidden channel EMI from the XB8.

Can someone please get a Network Engineer in here or to contact me to determine why the local or Seattle CMTS doesn't like my CM300 and throttles it?  "MAYBE" the buried line replacement helps signal quality enough to solve this.  Maybe the CM3000 or the CMTS are being overly sensitive to the signal degradation...??  But the CM1100 keeps chugging along...??

Help!  Please!  Thank you!