During a drying cycle, the whirlpool duet dryer door pops open, the indicators are flashing and even if I close and restart the cycle, the door pops open every few minutes.

A fairly common problem! The official instructions are

Before using your dryer, wipe the dryer drum with a damp cloth to
remove dust from storing and shipping.
1. Load clothes loosely into the dryer and close the door. Do not
pack the dryer. Allow space for clothes to tumble freely.
2. Turn the Cycle Control knob to the recommended cycle for the type of load being dried. Use the Energy Preferred Automatic Setting (,) to dry most heavyweight and medium weight loads. See "Drying, Cycle, and Temperature Tips."
3. Select a temperature setting on models with a Temp/Fabric selector. The cycle descriptions include temperature setting suggestions.
4. Push the START button.

Stopping and Restarting
You can stop your dryer any time during a cycle.
To stop your dryer
Open the dryer door or turn the Cycle Control knob to OFE
NOTE: The Cycle Control knob should point to an Off area when
the dryer is not in use.
To restart your dryer
1. Close the door.
2. Select a new cycle and temperature (if desired).
3. Press START

Extracted from
http://www.manualslib.com/manual/511763/Whirlpool-Lte5243dq.html?page=10#manual

The latch is shot I would replace both top and bottom. Most of the time all you need is a needle nose plier to perform the task. There are some good tutorials online that walk you through the steps. The actual latches a fairly inexpensive and you should be able to find them from a supply store that specifies in home appliance repair.

279570
Whirlpool 279570 Door Latch Kit AppliancePartsPros com


Easy Peasy

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those have a 2 latch system, sounds like the second latch that engages during the spin cycle never quite completed the safety lock , you could try and jumper the latch to see if that would release it, But it seems the secondary latch wasn't working properly in the first place, even the heaviest loads shouldn't pop the door open,

DOOR SWITCH ERROR

If the door has not been opened for 3 consecutive cycles or the door switch is open while the door is locked for more than 5 seconds.

Possible Causes/Procedure

-Door not opened during 3 consecutive cycles.

1. Open and close the door.
2. Verify CCU operation by running a Diagnostic Test or any cycle.

-Door switch open while door is locked.

1. Push the door and check if it is completely closed.
2. Verify CCU operation by running a Diagnostic Test or any cycle.

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We had the same problem and surprised how rampant the issue was after referring to the internet reviews / troubleshooting, etc. The problem started after about 6 months and the solution came to me after much "headaching" over the problem. There were no 'codes' coming up just the door popping open during the cycle. I purchased a (2) twenty pack of 1/2" diamerter x 1/16" thick N42 Neo Earth Magnets and placed them along the top edge and bottom edge of the dryer opening. Instant fix in less than a minute. The thickness does not interfere with the door opening and the strength of the magnets is obvious. Hope this helps. Fix was less than $10 bucks and no service man, etc.

If the door is popping open, that is causing the stoppage. There may be a way to adjust it, but I would have the people you bought it from fix it!! Best to have the device (spring/clip) that holds it closed replaced so it will give you longer life.

Peace,

call the dealer or manfacturer or read the manualo

Yes - before the lock/latch break instead.

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Chances are the little plastic latch keep is broken. Look at the door and locate a peice that will press into the front area where the clothes go in.
Once you see it, check the keeper and see if it is broken. The door should not just pop open.