Self descriptive: dismounting from any horse has a reasonable chance to cause damage to the horse, but not the player. The last time this happened to me, it killed the horse.
Linked issues
Comments
migrated
migrated
Please search for that issue on the MC:PE section of the bugtracker. This is the MC:PC section. If that issue doesn't yet exist in that section, create a new report for it.
Yes, it this isn't happen to me, but in lan multiplayer, almost all my friend horses died because of this issue (mcpe 0.15.0b3)