This problem has happened to me about 4 times within the past month; basically I'll be riding a tamed horse in survival mode and then the game crashes. I then immediately restart the program and find myself back at the exact same coordinates as before it crashed except on the ground with no trace of horse or the saddle/armor that was on it before. Before going straight to "it's a bug" I looked everywhere in a 50 block radius with no trace of horse/saddle. This is just such a frustrating issue because the last time I was in hard mode and ended up having to walk through a desert where I died of starvation lol.