Xbee 3 Digital IO passing not working


I have a pair of Xbee 3 radios set to use 802.15.4. I am trying to pass DIO4 from one to the other. I have them configured to the point where the serial console on the receiving node shows the DIO4 status every time I change the input on the sending node, but the output on the receiving node does not change.

I have tried setting the IA parameter to the address of the sending node as well as 0xFFFF, and have enabled DIO4 as Digital Input on the sending node and Digital Output, High on the receiving node. The PAN IDs and channels are the same, and test frames sent between the two work fine.

I have all the output timeouts set to 0 seconds, and the IU parameter is set to 1.

The sending node is configured as the coordinator and the receiving node is configured as an end device.

Both are set up with API mode without escapes.

Is there something else I need to do here to make this work? I am probably overlooking a small detail…