Disappearing mobs and blocks

I tamed and named a horse it disappeared when I logged into the realm never to return. Tamed and named a new horse, same spot, same problem. Repeated the processes again but changing it to a 4x4x4 box around 20 blocks from the original location. I logged in and not only did my horse disappear, but half one side of my oxidized copper 2x3 redstone door disappeared. My mule also disappeared from a larger room around 10 blocks from the door. My five axolotls disappeared from their pond but could not have escaped. I asked my friends but they were not on the realm or their devices during this time in which the previously listed events occurred. For that reason I cannot conclude it was trolling. In addition only one guy knows the cords of my base.
In short, in Minecraft realms mobs and blocks connected pistons have disappeared and not returned. Please fix!