Two switches SG3452X 1.20 with one TL-SM5310-T RJ45 each, connected to Synology E10G18-T1 and Synology E10G30-T2 respectively.
The switches are getting DDM alerts 1-2 times are day. Temperatures of the modules are about 71 degC. The server room is controlled at 18 degC.
Highest observed temperature of any of them was 77 degC with activity.
Changing cables from CAT6 to CAT6A (5m) did reduce the temperatures slightly but did not stopped alerts.
The switches stay at firmware 1.20.2 Build 20240115 Rel.73737 because upgrade to any subsequent  firmware causes SFP ports to flap about every 10-15 minutes.
The switches are in standalone mode.
LOGS excerpts

Switch 1
#2025-11-13 12:12:03,[DDM]/6/Port 49 SFP Module voltage is lower than alarm point.
#2025-11-13 12:12:03,[DDM]/6/Port 49 SFP Module voltage is lower than warning point.
#2025-11-13 12:12:03,[DDM]/6/Port 49 SFP Module bias current is higher than alarm point.
#2025-11-13 12:12:03,[DDM]/6/Port 49 SFP Module bias current is higher than warning point.
#2025-11-13 12:12:03,[DDM]/6/Port 49 SFP Module tx power is higher than alarm point.
#2025-11-13 12:12:03,[DDM]/6/Port 49 SFP Module tx power is higher than warning point.
#2025-11-13 12:12:34,[DDM]/6/Port 49 SFP Module voltage recover from the low alarm threshold.
#2025-11-13 12:12:34,[DDM]/6/Port 49 SFP Module voltage recover from the low warning threshold.
#2025-11-13 12:12:34,[DDM]/6/Port 49 SFP Module bias current recover from the high alarm threshold.
#2025-11-13 12:12:34,[DDM]/6/Port 49 SFP Module bias current recover from the high warning threshold.
#2025-11-13 12:12:34,[DDM]/6/Port 49 SFP Module tx power recover from the high alarm threshold.
#2025-11-13 12:12:34,[DDM]/6/Port 49 SFP Module tx power recover from the high warning threshold.

#2025-11-14 03:34:22,[DDM]/6/Port 49 SFP Module voltage is higher than alarm point.
#2025-11-14 03:34:22,[DDM]/6/Port 49 SFP Module voltage is higher than warning point.
#2025-11-14 03:34:22,[DDM]/6/Port 49 SFP Module bias current is higher than alarm point.
#2025-11-14 03:34:22,[DDM]/6/Port 49 SFP Module bias current is higher than warning point.
#2025-11-14 03:34:22,[DDM]/6/Port 49 SFP Module tx power is higher than alarm point.
#2025-11-14 03:34:22,[DDM]/6/Port 49 SFP Module tx power is higher than warning point.
#2025-11-14 03:34:22,[DDM]/6/Port 49 SFP Module rx power is higher than alarm point.
#2025-11-14 03:34:22,[DDM]/6/Port 49 SFP Module rx power is higher than warning point.
#2025-11-14 03:34:52,[DDM]/6/Port 49 SFP Module voltage recover from the high alarm threshold.
#2025-11-14 03:34:52,[DDM]/6/Port 49 SFP Module voltage recover from the high warning threshold.
#2025-11-14 03:34:52,[DDM]/6/Port 49 SFP Module bias current recover from the high alarm threshold.
#2025-11-14 03:34:52,[DDM]/6/Port 49 SFP Module bias current recover from the high warning threshold.
#2025-11-14 03:34:52,[DDM]/6/Port 49 SFP Module tx power recover from the high alarm threshold.
#2025-11-14 03:34:52,[DDM]/6/Port 49 SFP Module tx power recover from the high warning threshold.
#2025-11-14 03:34:52,[DDM]/6/Port 49 SFP Module rx power recover from the high alarm threshold.
#2025-11-14 03:34:52,[DDM]/6/Port 49 SFP Module rx power recover from the high warning threshold.

Switch 2 (an odd temperature alert)
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module temperature is higher than warning point.
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module voltage is lower than alarm point.
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module voltage is lower than warning point.
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module bias current is lower than alarm point.
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module bias current is lower than warning point.
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module tx power is higher than alarm point.
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module tx power is higher than warning point.
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module rx power is higher than alarm point.
#2025-11-14 15:04:06,[DDM]/6/Port 49 SFP Module rx power is higher than warning point.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module temperature recover from the high warning threshold.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module voltage recover from the low alarm threshold.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module voltage recover from the low warning threshold.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module bias current recover from the low alarm threshold.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module bias current recover from the low warning threshold.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module tx power recover from the high alarm threshold.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module tx power recover from the high warning threshold.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module rx power recover from the high alarm threshold.
#2025-11-14 15:04:37,[DDM]/6/Port 49 SFP Module rx power recover from the high warning threshold.

#2025-11-15 00:23:52,[DDM]/6/Port 49 SFP Module voltage is higher than alarm point.
#2025-11-15 00:23:52,[DDM]/6/Port 49 SFP Module voltage is higher than warning point.
#2025-11-15 00:23:52,[DDM]/6/Port 49 SFP Module bias current is higher than alarm point.
#2025-11-15 00:23:52,[DDM]/6/Port 49 SFP Module bias current is higher than warning point.
#2025-11-15 00:23:52,[DDM]/6/Port 49 SFP Module tx power is higher than warning point.
#2025-11-15 00:24:53,[DDM]/6/Port 49 SFP Module voltage recover from the high alarm threshold.
#2025-11-15 00:24:53,[DDM]/6/Port 49 SFP Module voltage recover from the high warning threshold.
#2025-11-15 00:24:53,[DDM]/6/Port 49 SFP Module bias current recover from the high alarm threshold.
#2025-11-15 00:24:53,[DDM]/6/Port 49 SFP Module bias current recover from the high warning threshold.
#2025-11-15 00:24:53,[DDM]/6/Port 49 SFP Module tx power recover from the high warning threshold.