When an axolotl spawns in air (not in water) using the "/summon minecraft:axolotl" command, it starts dying immediately. Although if you spawn him with a summoning egg, he can calmly move along the ground without gasping for breath. Here is a short video demonstrating the problem: https://drive.google.com/file/d/1CEKGEPvnc8k4BzLo-ME9OgfYWqMPk_BY/view?usp=sharing