I've discovered that the dragon breath in the Bedrock version of Minecraft seems to deal an insane amount of damage and knockback. I also noticed that it sits around for around two minutes(compared to java in which it stays for 30 seconds). In Java, the damage is not as frequent and the knockback is reduced. I consider this a bug because I don't think you should get killed in under 10 seconds by the dragon breath with fully enchanted armor.
Thank you.
This issue is already tracked at MCPE-40344