When you open an automation track for the first time, it does not contain any automation events. This is indicated by a dotted horizontal line, the static value line, in the event display. This line represents the current parameter setting.
If you manually add any automation events or use write automation for the corresponding parameter and then disable the reading of automation data, the automation curve is grayed out and the static value line is used instead.
As soon as Read is enabled, the automation curve is used.