Placing a player head makes the game stutter or crash

Have you tried to give to yourself a head of a player who does not exists?

No, i only tried with the head of my character

Could you try to reproduce it again?

On 1.14.4-pre2:
The game crashed whilst unexpected error
Error: java.util.ConcurrentModificationException
using this head: give @p minecraft:player_head{SkullOwner:{Name:"Giuseppe2018"}} 1
On 1.14.3 works fine

Does it work if you do
/give @p minecraft:player_head{"SkullOwner":"Giuseppe2018"}

Yes it works, no problem

Forward resolving to MC-159202