unwanted / random switch off

[Adso76]

Hi,
I have several relays connected to Domitcz via PCF8574. Some of them from time to time randomly and without any command switch off.
For example one the screen you will find logs of one of them - in red frame you can see switch off, which was unplanned.

screen20190821.png (123.98 KiB) Viewed 904 times

At the same time in general Domotich logs there was nothing.
This switch has two timers set ("on" command at 20:20 and "off" command at "07:00").
Can you explain this?