@Ramias,

Do these happen to be handling high-capacity devices? Could it be that they are shutting off as a protective measure?

Otherwise, make sure that you did not accidentally create a smart action for the devices in the Kasa App. Previously, when someone saw this, it was actually caused by the device being added to a third-party app (Smartthings), which then automatically added the device to a daily routine that they had created before - so i would check any apps that you have connected your Kasaaccount to for any automations.

Has the behavior continued? Is it possible that the device rebooted to apply an update?

I would recommend resetting one of the devices to factory defaults to see if the behavior occurs on both when it happens again.

  @Ramias,

This sounds very similar to a reported behavior that was patched quite a while ago, I would check your firmware versions just to be sure.

Otherwise, take a look at the thread on the global forums to see if it describes what you are facing: https://community.tp-link.com/en/smart-home/forum/topic/262328

There are troubleshooting steps provided in the thread, so make sure to try the isolation settings and disabling beamforming/fast roaming to see if there is any discernible difference.