Angry Birds: score is always 3,977,990

I played all (available) levels of Angry Birds Summer PigNic and always get 3,977,990 as a score, for all levels (score displayed top right side).

Please see the screenshot below (today's level)

The score takes about 3 mn (three minutes) to be displayed - counting from 1 to 3,977,990.

What does that score mean? Is it be a bug or a kind of limit feature?

I believe that's your highest score so far for a set of levels, presumably the Trick or Treat levels. As for why it shows and counts it every time ... that's either a bug or a really dumb decision made by Rovio. It doesn't happen on the Android version.

Note that the highscore for the level is shown below it on the yellow tab, and the current score below and left of that on the green area.