Dragon takes less damage than it should unless you hit its neck/head with a projectile

When normally fighting the ender dragon, it has about 600 HP instead of 200 unless you land a projectile (arrow, snowball, ender pearl etc.) on the dragons neck. Only then will the dragons health revert back to 200 and everything appears to deal 3x more damage.

This affects every Version of bedrock edition since 1.2.