If you adjust your max_health attribute to be lower than default and take damage from apparently any source other than fall damage your player model will glitch out and you will receive a death message even though you are still alive. Pressing respawn will remove the message without you respawning and you will be able to continue to play as normal, just with a very glitched player model.

To reproduce:
1. run the command: /attribute @s minecraft:generic.max_health base set 10
2. take damage in any way other than falling, such as via a skeleton: /summon minecraft:skeleton ~ ~ ~
3. Use F5 or open your inventory to see the player model appear to be dead while still being alive

You can use many other damage forms as well to reproduce this including using instant damage potions or summoning an arrow directly above your head. Fall damage DOES NOT seem to cause this glitch.