Because, vilas, you are quoting the logic of the actual system.
The OP is trying to find a suggestion for a software monitoring routine of that system. At the moment the their setup is
OPEN IN FLIGHT => Failure message generated
OPEN ON GROUND => all good.
Unfortunately, ON GROUND and IN FLIGHT is already coded in that monitoring software via “phase” concept, ON GROUND being triggered by NLG weight-on-wheels. Which create false warnings every landing, because pilots do open REV well before NLG because
- it is the right thing to do
- it is certified as such
- the logic of the actual system (which you described) allows it