This relates maybe to: MC-52653 and MC-65587

It seems like everytime you give yourselft a skull and the SkullOwner tag contains something with "MHF_" the game freezes (probably because of MC-65587), BUT also when placing it
How to reproduce

• /give @p skull 1 3 {SkullOwner:MHF}

  mhf is a player, no lag while placing

• /give @p skull 1 3 {SkullOwner:MHF_1}

  MHF_1 is a player, lag while placing

• /give @p skull 1 3 {SkullOwner:MHF_2}

  MHF_2 is probably not a player, lag while placing

• /give @p skull 1 3 {SkullOwner:MHF_sheep}

  MHF_sheep is added by MOJANG, no lag while placing

it seems like it freezes or lags not every time, sometimes it has only a delay