The Multiplier resets when any five-star bird is obtained; therefore, receiving a five-star bird will mean the multiplier resets back to the beginning. Hatching further will continue to increase this multiplier, and this is why it may sometimes appear as reduced as a five-star bird has been most likely obtained during that process.
My hatching multiplier reset or was reduced, but I did not notice receiving an event 5-star bird.
Last Updated: 76d