Turned off or Turned on is the disable or enable action. If it’s changed by something in HA it should show what the trigger was too (like a user or other automation).
Here’s an example - it shows the automations that enabled our disabled this automation, and their trigger.
To prevent the automation from being changed you can rename it, that should break anything automatic that’s changing it. You can also try to chase down what’s changing it from logs (once renamed you should start seeing errors in your HA log file), or by searching for the entity_id in your yaml configuration files.