That is a hard problem. One hint may be the screw to fix the thermistor. Heater block expands differently then thermistor so if you screwed too hard you might get a thermistor defect somehow.

There is also a difference between decoupled and defect. Defect is this test:

if(act->currentTemperatureC < MIN_DEFECT_TEMPERATURE || act->currentTemperatureC > MAX_DEFECT_TEMPERATURE) // no temp sensor or short in sensor, disable heater

{

errorDetected = 1;

if(extruderTempErrors < 10) // Ignore short temporary failures

extruderTempErrors++;

else

{

act->flags |= TEMPERATURE_CONTROLLER_FLAG_SENSDEFECT;

if(!Printer::isAnyTempsensorDefect())

{

Printer::setAnyTempsensorDefect();

reportTempsensorError();

}

EVENT_HEATER_DEFECT(controller);

}

reading the code I would like you to modify a few lines later

bool decoupleTestRequired = !errorDetected && act->decoupleTestPeriod > 0 && (time - act->lastDecoupleTest) > act->decoupleTestPeriod; // time enough for temperature change?

I added "!errorDetected && " here to not test for decouple on defect error. A defect sensor is always out of range and could otherwise trigger decoupled instead and speeds up counter increment more then wanted.

The line if(extruderTempErrors < 10) has already a multiple test. The routine gets called 10 times per second, so you need to have the error for a full second to get it, not only for one reading.

Last thing is check your temperature graph. It should be a more or less continuous line without big jumps. Heating and cooling has a maximum speed and bigger jumps are reading errors compared to reality and do not happy with correct printers (I know you knew this already :-).