This does indeed sound like it could be solved by simply checking the "every frame" option.
In case you are not familiar with it, the difference between having "every frame" on and off is simple.
With "every frame" OFF, the action in question will be performed ONCE and no more after that, unless you go back to the state again. This is most likely what is happening to you - when the turret enters the "look at player" state, it will get the players position and rotate to it ONCE and then just stay there doing nothing.
When "every frame" is ON, the action in question will perform in every frame, meaning constantly, and will not stop until you exit the state. This will make your turret constantly updating the players position, and rotating to it. If you are using the "finished" transitions, "every frame" also means that the transition will not be called, as the state never really finishes (because it will keep performing your action and never stop), so to move to another state, you could simply use a "send event" action, a "wait" action (if you want to go to another state after a ceartain amount of time) or use any other action like get distance or raycast to trigger transitions.
I hope this helps
And welcome to playmaker!
-Koz