I am having the exact some problem, I bought 2 units already on separate occasion. I bought the 2nd unit to replace the first unit which also had the same problem. Each unit last about 6 months. 

Seems this is a wide-known problem, I am looking for a replacement now but for sure I will change brand. No more TP Link as its not so reliable...

@Saski 

Good day,

May I know where are you located and have you got the replacement already?

Did the replacement work well?

Since recently, we are trying to collect some samples for further assistance.

Really sorry for the inconvenience.

Thanks a lot.

@Mikeyboyzzz 

Just plugged mine in and linked to Kasa app, plug will not turn off. Led turns off and i can hear plug click, but power continues through socket.... Brand new...

@Mikeyboyzzz Same issue with two of these, they seem to work for a while, and then the switch stops working. You can see the light switching off and you can hear the relay click, but power remains on.

Can return under warranty (again) but clearly a design fault which is a shame as they are useful devices

@Simon_M999 same issue here. Based in Ireland and lasted less than 6 months. I  use to tp link stuff all over the place and this is the first device that seems to have a common fault. Based in Ireland if you wanted data (saw looking for details in previous thread). If there is a more durable version I can buy to replace let me know. Cant be bothered with warranty nonsense.

@Abean I am also having this issue.  Can I check which model you are having issue with as mine is the newer kp115 version 1.

 Mine worked for approximately 6 months then stopped with the same symptoms.  I have an rma on that one but I got a new from Amazon and that's lasted two days :(

I do have a power strip with a couple of laptops and monitors plugged into it but in normal usage it's less than 300W and even at peak can't be more than 650w combined.  I can't see an in rush current being that much more and given they are rated at 13 A .

 Haven't so far had an issue with the previous model and that was running the same setup but didn't have energy monitor, which is why I swapped.

@ChuckVader yes mine were kp115 devices. After I had two of these devices fail, I have switched to another brand which is working fine so far

Just want to add my name to this, I've had 3 of these fail, the relays get stuck and will not turn off, you still hear a click but it's not as loud when they fail, giving them a good wack can release the relay for a while but eventually they end up in the bin. 

Sorry TP Link your smart plugs have been a disappointment for me. 

@MikeP 

Same issue but seem to have fixed with 4 or 5 rapid short presses of the power button on the side of the smart plug and the power to the lights the smart plug was connected to went off and then back on and I was then able to control with app again