The game freezes for a few seconds, if you give yourself the head of any player with the command (/give @p skull 1 3 {SkullOwner:Notch} for example).
MC-118343
The problems with the issuance of the head of any player (/give)
Resolved
Duplicate
0
MaxZoneNP
(Unassigned)
Unconfirmed
Minecraft 1.11.2, Minecraft 1.12 Pre-Release 6, Minecraft 1.12 Pre-Release 7
Retrieved
The game needs to connect to the skin servers, download the texture and convert it to a string to store it in the head; this is not fixable.