In my server almost all bedrock player suffer from horse dying when they dismount. Java player doesn't have any problem.
Edit: I know it’s kind of an old problem but I’m running Java 1.24.4 for my server so not sure why this issue still exists. Previous support article I found mentioned about in bedrock edition, horses fall damage did not work properly while a player is mounted. When player dismount, accumulated damage will activate and kills the horse immediately. I’m not sure why it happens in a version that supposedly fixed this error.
#Bedrock player horse killed while dismounting.
odd urchin
woven linden
My players have been reporting this problem on my server too
I have yet to replicate it though, but the way they describe it matches your description as well
dusty light
This is true; the horse doesn't take any fall damage and when you dismount, it takes all the accumulated damage
brittle dirge
i have a user that has reported this twice in the last 24 hours. they got a video of it the second time and it's exactly as you describe. the horse appears to have taken no damage while riding it, but then upon dismounting the horse immediately dies from fall damage and the saddle is picked up by the player.
as it was a named horse i checked the server log and it definitely reports the horse as having died from fall damage..