When moving the cursor over pure RTL text in TextField, the caret moves forwards (left-wards) until it hits the last position, i.e. the position after the last character, and then  it jumps to the far right again.

Here is a simple test case:

import javafx.application.*;
import javafx.scene.shape.*;
import javafx.scene.text.*;
import javafx.stage.*;

public class TextTest extends Application {

    public static void main(String[] args) { launch(args); }

    @Override public void start(Stage stage) {
        Text text = new Text("\u05E9\u05E0");

        for (int i = 0; i <= text.getText().length(); i++) {
            text.setImpl_caretPosition(i);
            System.err.println("caretPos=" + i + ", caretX=" + ((MoveTo)text.getImpl_caretShape()[0]).getX());
        }
        System.exit(0);
    }
}

Output:
caretPos=0, caretX=14.41552734375
caretPos=1, caretX=5.205078125
caretPos=2, caretX=14.41552734375