Extreme lag when attaching Happy Ghast to a fence using a lead (1.21.6, Switch & Bedrock)

When I attach a Happy Ghast to a fence using a lead, Minecraft Bedrock starts to lag extremely. The performance drops instantly:

• Blocks disappear when placed or don’t register at all.

• Severe frame drops and input delay.

• Game freezes frequently, even in Creative mode.

• Issue continues even with all other mobs, items, and redstone removed.

• Happens on both small and large worlds.

• Lag disappears when the Happy Ghast is removed or not tied.