Xbee Digital IO Line Passing endpoint changes port state after 15 seconds without input change

I have XB24C (S2C) modules loaded with 802.15.4 FW (version 2001). Network is build with 1 coordinator and 4 endpoints. Line passing is configured as it is described on the Digi Knowledge Base articles. Coordinator has the input and endpoints have the output.

When INPUT(Coord) is logic low, the output on all endpoints go low as expected.
Input stays low but after ~15 seconds all modules releases the line, that means output goes high, even if the input does not change.

The manual says if T[x] parameter is set to “FF” the output pin keeps the state but that does not happen.

I set INPUT(Coord) to send the state on every 10 seconds but this is not the wanted solution.

So how that can be solved?

After reading the user manual, it turns out that this behavior is the default for the system. So switching to API mode on the coordinator side solves the issue.