SBG8300 - Intermittent Outages - 32QAM Upstream Noise - Verified Direct Drop

I am experiencing intermittent outages (T3 Timeouts and DHCPv6 Option 82 errors). I have performed a Direct Drop test (modem connected directly to the service entrance, bypassing all internal splitters/extenders) and the issue persists. Signal Data:

• Upstream Modulation: 32QAM on 3/4 channels.

• Upstream Power: 36 dBmV (Low/Borderline for SBG8300 specs).

• Downstream Power: +9.5 dBmV (High/Hot).

Key Diagnostics (Verified at Direct Drop):

• Upstream Modulation: Stuck at 32QAM on 3 out of 4 channels (Partial Service).

• Upstream Transmit Power: 36.7 dBmV (Low; close to the noise floor for this model).

• Downstream Power: +9.5 dBmV (Hot/High across several frequencies).

• Event Logs: Repeated No Ranging Response received - T3 time-out and DHCPv6 - Missing Required Option 82.

Troubleshooting Already Performed:

1. Direct Drop Test: Modem was connected directly to the service entrance/ground block; 32QAM and high downstream power persisted. Internal wiring/extender has been ruled out.

2. Environment: Network equipment is kept in a climate-controlled room (Humidifier removed).

3. Local Network: Speed bottlenecks were identified as Zscaler-related, but the Physical Layer instability (T3/32QAM) remains the root cause of the drops.

Requested Action:

• Check Upstream SNR and Ingress at the tap and ground block.

• Balance signal levels to bring Upstream Power closer to 45 dBmV and Downstream Power closer to 0 dBmV.

Here are the logs from my router