For comparison to ethtool's output that shows incorrect threshold values, when installing the same transceiver in a Cisco Nexus switch, and issuing the Cisco command "show interface ethernet 1/3 transceiver details", the switch correctly correctly reads/displays the transceiver's Alarm and Warning thresholds, as shown below:


switch# show interface ethernet 1/3 transceiver details 
Ethernet1/3
    transceiver is present
    type is QSFP-100G-CWDM4-MSA-FEC
    name is TRANSITION
    part number is TNQSFP100GCWDM4
    revision is 1A
    serial number is TN02000302
    nominal bitrate is 25500 MBit/sec per channel
    Link length supported for 9/125um fiber is 2 km
    cisco id is 17
    cisco extended id number is 252

Lane Number:1 Network Lane
           SFP Detail Diagnostics Information (internal calibration)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   38.08 C        80.00 C    -10.00 C     75.00 C       -5.00 C
  Voltage        3.34 V         3.70 V      2.90 V      3.59 V        3.00 V
  Current       34.24 mA       75.00 mA    10.00 mA    70.00 mA      15.00 mA
  Tx Power      -0.44 dBm       4.49 dBm   -8.50 dBm    3.49 dBm     -7.52 dBm
  Rx Power          N/A         4.49 dBm  -14.55 dBm    3.49 dBm    -12.51 dBm
  Transmit Fault Count = 0
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

Lane Number:2 Network Lane
           SFP Detail Diagnostics Information (internal calibration)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   38.08 C        80.00 C    -10.00 C     75.00 C       -5.00 C
  Voltage        3.34 V         3.70 V      2.90 V      3.59 V        3.00 V
  Current       34.24 mA       75.00 mA    10.00 mA    70.00 mA      15.00 mA
  Tx Power      -1.20 dBm       4.49 dBm   -8.50 dBm    3.49 dBm     -7.52 dBm
  Rx Power          N/A         4.49 dBm  -14.55 dBm    3.49 dBm    -12.51 dBm
  Transmit Fault Count = 0
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

Lane Number:3 Network Lane
           SFP Detail Diagnostics Information (internal calibration)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   38.08 C        80.00 C    -10.00 C     75.00 C       -5.00 C
  Voltage        3.34 V         3.70 V      2.90 V      3.59 V        3.00 V
  Current       33.21 mA       75.00 mA    10.00 mA    70.00 mA      15.00 mA
  Tx Power      -0.96 dBm       4.49 dBm   -8.50 dBm    3.49 dBm     -7.52 dBm
  Rx Power          N/A         4.49 dBm  -14.55 dBm    3.49 dBm    -12.51 dBm
  Transmit Fault Count = 0
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

Lane Number:4 Network Lane
           SFP Detail Diagnostics Information (internal calibration)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   38.08 C        80.00 C    -10.00 C     75.00 C       -5.00 C
  Voltage        3.34 V         3.70 V      2.90 V      3.59 V        3.00 V
  Current       33.72 mA       75.00 mA    10.00 mA    70.00 mA      15.00 mA
  Tx Power      -1.59 dBm       4.49 dBm   -8.50 dBm    3.49 dBm     -7.52 dBm
  Rx Power          N/A         4.49 dBm  -14.55 dBm    3.49 dBm    -12.51 dBm
  Transmit Fault Count = 0
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

switch#