SPOILER or technical issue?

I approached a bird cage with 3 parrots before, as I approached it, the parrots went crazy, flipping etc. (as it was back there in Maldives mission)
Now I found many items, took some new photographs, working on the case… etc
Now I approach the cage, parrots are frozen.
Now I guess they are poisoned or something… Or it’s a glitch / bug?

I think if you load a save they froze. Not sure though. Happened to me too.

Anyway, I just solved the case and finished the level, so it was not essential for the story. Maybe the parrots are here for some challenge or something.