RAK12035 can't sleep the sensors

I have an application using:
RAK5005-O
RAK4631
RAK12023 with three RAK12035

Any time I try to sleep the sensors, my app locks up requiring a hard power cycle. As soon as I sleep the sensors I never see my timers wake up the app, nothing logged, etc - that’s what I mean by locked up.

If I do not do the sensor_sleep, the sensors and application work correctly, but power usage is pretty high.

Any thoughts?

        // Sensor definition
       RAK12035 sensor;
       RAK12035 sensor2(0x21);
       RAK12035 sensor3(0x22);

        // This is in my loop, and crashes the app for some reason
        sensor.sensor_sleep();
        sensor2.sensor_sleep();
        sensor3.sensor_sleep();

As another data point, if I run this example ( https://raw.githubusercontent.com/RAKWireless/RAK12035_SoilMoisture/main/examples/RAK12035_LowPower/RAK12035_LowPower.ino ) with no modifications at all, I get this:

Sensor Firmware version: 0x02
Dry calibration value is 565
Wet calibration value is 570
Soil Moisture Capacitance: 554
Soil Moisture humidity(%): 100
Soil Moisture Temperatur: 26 *C
Put the sensor into sleep mode for 2 minutes

And then it never runs again. if I comment out the sensor_sleep line it runs every 2 minutes as expected.

I guess for now I’ll just use IO2 to power off the sensors between readings. That seems to work as expected.