It seems hdl coder adds this state IN_NO_ACTIVE_CHILD by itself for the case where the state machine moves to the OFF state as shown below from the vhdl generated.
--case IN_ON:
sf_internal_predicateoutput_0 := hdlcoder_to_stdlogic((( NOT onoff) OR hdlcoder_to_stdlogic(timeoutCycles_unsigned = to_unsigned(0, 32))) = '1');
IF sf_internal_predicateoutput_0 = '1' THEN
is_COUNT_IS_VALID_next <= IN_NO_ACTIVE_CHILD;
is_TIMEOUT_WATCHER_next <= IN_NO_ACTIVE_CHILD;
is_timer_chart1_next <= IN_OFF;
ELSE
I am totally confused by why hdl coder would complain something it did itself. To me it would have made sense to move them back to the state connected to the default transitions????