Update:

I turned it on long enough to get a log and this time it's reporting temp sensor errors from two boards:

Sun Jan 30 09:23:28 2022 daemon.err bosminer[1632]: Jan 30 16:23:28.484 ERROR bosminer_hal::sensor: Sensor hb3.11[ii_hwmon::tmp451::TMP451]: read failed: I2C error: general error Hashchip: no response for read_register(reg=0x1c) from chip One(11)

<snip>

Sun Jan 30 09:23:29 2022 daemon.err bosminer[1632]: Jan 30 16:23:29.918 ERROR bosminer_hal::sensor: Sensor hb2.8[ii_hwmon::tmp451::TMP451]: read failed: I2C error: general error Hashchip: no response for read_register(reg=0x1c) from chip One(

<snip>

Sun Jan 30 09:23:30 2022 daemon.err bosminer[1632]: Jan 30 16:23:30.020 ERROR bosminer_hal::sensor: Sensor hb2.36[ii_hwmon::tmp451::TMP451]: read failed: I2C error: general error Hashchip: no response for read_register(reg=0x1c) from chip One(36)

<snip>

Sun Jan 30 09:25:03 2022 daemon.err bosminer[1632]: Jan 30 16:25:03.696 ERROR bosminer_hal::sensor: Sensor hb3.8[ii_hwmon::tmp451::TMP451]: read failed: I2C error: general error Hashchip: no response for read_register(reg=0x1c) from chip One(
Sun Jan 30 09:25:03 2022 daemon.err bosminer[1632]: Jan 30 16:25:03.797 ERROR bosminer_hal::sensor: Sensor hb3.36[ii_hwmon::tmp451::TMP451]: read failed: I2C error: general error Hashchip: no response for read_register(reg=0x1c) from chip One(36)

Assuming I'm correct in interpreting the sensor IDs, looks like there are 2x sensors on hashboard 2, and 3x on hashboard 3 that aren't communicating.

Further assuming there's nothing to do about this myself if I don't trust my soldering skills in this context?