Why does device discovery cause MicroPython to stop running on my sleeping end device?

I have several end devices configured for MicroPython Sleep (SM 6). In XCTU, if I do a device discovery-- click on the button to “Discover radio modules in the same network”-- the end devices will sometimes exit sleep, and not return. MicroPython execution is also stopped, requiring me to physically reset the device. Any ideas how this state can be detected/avoided?

You need to use the Micro Python sleep() function.

I’m calling module.sleep_now(60000) in a while loop, where module is instantiated as xbee.XBee(), so the device should re-enter sleep mode after a minute or so. But it doesn’t.