Ender dragon loses its AI after perching on a block at Y≥107 with no nearby players in survival or adventure mode

When the ender dragon goes to perch, it will perch on top of the highest block at 0, 0. If that block is at Y=107 or higher, the ender dragon will (at least sometimes) lose its AI after perching if there are no nearby players in survival or adventure mode (although its NoAI will remain 0b). While it is in this state, if the perch column (the block it is perching on and the next several blocks below it) become air, the ender dragon will immediately regain its AI.

I do not think this bug lends itself to a practical survival exploit. I have tried camping near the perch block and then pearling to the ground and reducing my render distance right as the dragon begins its perch but this did not work, the bug only seems to happen when I involve creative or spectator mode in some way. A tactical suicide (so that you are dying as the dragon attempts to leave its perch) may freeze it but is completely impractical, especially since there is no good way to predict how long the dragon will remain perched for. All in all, this bug is more of a curiosity than anything else.

The attached video (which can’t be seen on the service portal due to META-212) shows me unsuccessfully attempting to exploit this in survival without using ender pearls (I’ve given myself Resistance V). As can be seen, the dragon simply files away after ending its perch when I am in survival mode, and only loses its AI if I am in creative mode.

To reproduce

1. Create a new world

2. /execute in minecraft:the_end run teleport @s 0 120 0 and enter creative flight immediately afterwards

3. /setblock 0 107 0 minecraft:end_stone

4. /kill @e[type=minecraft:end_crystal] (because the dragon perches more frequently the more end crystals are destroyed

5. /tick sprint 1d
   ❌ The dragon will eventually lose its AI after perching on the placed block

6. /tick sprint stop

P.S.

This is in my opinion one of the less important bugs with the ender dragon, the big outstanding ones are MC-197201 (and the related MC-271336), MC-227327, MC-85100 (WAI for some reason), MC-91636 and MC-102774. In the event you would rather rework the dragon fight entirely rather than fix all these bugs (which I support because the current fight isn’t all that fun), I made a feedback post detailing my vision for that.