Two items on one thing

[vzorglub (Vincent Regaud)]

In the mean time I tidied up your rules a bit
I used the postUpdate method for the item Porch_Light_Auto because I assume that is just a flag item with no binding and a postUpdate is sufficient
I used the sendCommand method for the item Porch_Light_Motion
In both cases I have used the method instead of the action as the item is known.
The explanation is here:

Textual Rules

I have also used a timer instead of your 9 seconds sleep
Thread::sleep should only be used if unavoidable and only for short periods (1s or less)
The explanation is here:

(OH 1.x and OH 2.x Rules DSL only] Why have my Rules stopped running? Why Thread::sleep is a bad idea

EDIT: While the general advice in this article still applies (i.e. it’s always worth while to make short running rules), the problem described in this article only applies to OH 1.x and Rules DSL in OH 2.x. In OH 3 and beyond, this is no longer a problem so if your rules stop running in any version of OH released in the last two years (as of this edit in 1/2023) this is not your problem. By way of explanation, in OH 3 each rule gets it’s own thread. It is no longer possible for a rule to starve…

var Timer timer = null

rule "Back Porch Lights Switch2"
when
    Item Porch_Light changed
then
    if (Porch_Light.state == ON) {
        Porch_Light_Auto.postUpdateOFF)
        logInfo("info", "Manual2 Lights Switched On.")
    }
    if (Porch_Light.state == OFF) {
        Porch_Light_Auto.postUpdate(ON)
        logInfo("info", "Manual2 Lights Switched Off.")
    }
end

rule "Back Door Motion"
when
    Item BackDoorCamMotion changed
then
    if (Daylight.state == OFF && Porch_Light_Auto.state == ON && BackDoorCamMotion.state 
== "Motion") {
        logInfo( "File", "Motion was detected at the back door at night.")
        Porch_Light_Motion.sendCommand(ON)
        if (timer === null) {
            timer = createTimer(now.plusSeconds(9), [ | 
                if(Porch_Light.state == ON) Porch_Light_Motion.sendCommand(OFF)
                timer = null // resets the timer
            ])
        }
    }        
end