PulseIn function sometimes lost long pulses

I count pulses f=425Hz duty 1:1 with 0.3s pause, then repeat pulses.
I write program, which check length of the pulses, (in general they are 1200mcs) and if find very long pulse (300000mcs) , program must to make action (set pin12 to HIGH).
It finds the long pulse only one time, and make, what it need.

The problem is : that it cannot to make it 2nd time! After pin12 set ON, and OFF, and need to continue cwait long pulse, it still count, but find short pulses only.

It helps by resetting board - it can find long pulse one more time.

Can somebody to advice something, for long pulses discovered any times, not only one time?

(i use Arduino Nano)

digitalWrite(InC, LOW);  // SETTING LOW FOR START PulseIn       
    Serial.println("Find duty 0.2 c in Call signal ");//switch level to high
    Serial.println("                      ");// 
    Serial.println("                      ");// 
    Serial.println("Now can take a call to voice  ");
     digitalWrite(SwTT, HIGH);  // pOWER relay to swtch to voice board
    //digitalWrite(SwTT, LOW);  // pOWER relay to swtch to line 
   else{ Serial.println("this is not a duty period");// say what you got:

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PulseDetector.ino (6.02 KB)