I was going to locate a stronghold while at my house (Which is at worldborder) and it said "The nearest stronghold is at [21049 ~ 10872] (0 blocks away)" and my house beneath it is void and above is sky, I teleported by clicking the coords and I checked my coords, nowhere near my house. (My house coords are at 498044 59 500107)

This is on a Server (Run at home on Linux) if that helps.