Terminal widget: printed message truncated or hold back

In my arduino program I use the following code to display a message on the terminal widget.
After I press the button V12 I would expect the text ‘Light’s on’ or ‘Light’s off’ to appear respectively in the widget.
But the widget shows e.g
Light’s on
where is the rest of the ‘Light’s off’ message? When I press the button again it might show
Light’s on
Light’s off
Light’s o
the reminder of the last message is shown but again the new message is truncated.
Somehow the message is stuck somewhere in a buffer? Any idea?

BLYNK_WRITE(V12) //Button Widget is writing to pin V12
int pinData = param.asInt();
if (pinData) {
digitalWrite(4,HIGH); //This is a relays attached to digital pin 4
Blynk.virtualWrite(V2,1); // This is a LED widget to show the push button V12 worked
terminal.println(“Light’s on”);
else {
terminal.println(“Light’s off”);

You have to call terminal.flush() to complete the writing of text blocks.
Take a look at the examples.