HAAD added hydrogen atoms without bonds

I've used the HAAD server to add hydrogen atoms to the PDB 2FD6. I don't know why, but some hydrogen atoms were added without any connections to other atoms. I've used the Discovery Studio to visualize the structure with hydrogen atoms generated by the HAAD and these "isolated" hydrogen atoms were generated with huge distances form the heavy atoms they shoud be connected. Have anyone ever had the same problem?

Thanks,
Pablo