Before Reading this, please note that the version I am using is Optifine 1.16.4, so this may be patched in later versions
If the Ender Dragon is at any level of health, leaving and rejoining the game resets the health of the dragon. The Images below show before and after leaving the game (Bossbar and Bossbar 2 respectively)
You can recreate this by going to the end, damaging the Ender Dragon, leaving the game, then Rejoining the game. Notice how the health bar is now back to full health
Attachments
Comments 2
Thank you for your report!
However, this issue is Invalid.
Your game, launcher or server is modified.
If you can reproduce the issue in a vanilla environment, please recreate the issue.
Any non-standard client/server/launcher build needs to be taken up with the appropriate team, not Mojang.
Any plugin issues need to be addressed to the creator of the plugin or resource pack.
If you have problems on large servers, such as The Hive and Hypixel, please contact them first as they run modified server software.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki
Invalid - Using a mod