Check incoming OSC arguments using Condition

if trigger == "value" then
    return true
else
    return false
end

I replaced "value" with 1 (the argument received is an integer). Put it in the quick script, and the log said:

17 Sep 10:35:00 Trigger 2000 rejected - conditions were not satisfied
17 Sep 10:35:00 CONDITION Script: script returned false
17 Sep 10:35:00 CONDITION Script: Quick Script executed successfully in 100 microseconds (mem in use = 58KB)
17 Sep 10:35:00 Trigger 2000 (IO Module): Matched
17 Sep 10:35:00 OSC /trigger args: 1

Any idea why it doesn't match?

I replaced "value" with 1 (the argument received is an integer). Put it in the quick script, and the log said:

17 Sep 10:35:00 Trigger 2000 rejected - conditions were not satisfied
17 Sep 10:35:00 CONDITION Script: script returned false
17 Sep 10:35:00 CONDITION Script: Quick Script executed successfully in 100 microseconds (mem in use = 58KB)
17 Sep 10:35:00 Trigger 2000 (IO Module): Matched
17 Sep 10:35:00 OSC /trigger args: 1

Any idea why it doesn't match?

log what the trigger is to debug

if trigger == 1 then
    return true
else
    log("*** Trigger input is "..trigger.." ***")
    return false
end

I replaced trigger with get_trigger_variable(1) in your original script and it works!