they didn’t change anything, you are missing vital information.
monster level =/= area level in normal. this is only true in nightmare and hell. normal has different logic.
the area level of chaos sanc is 28, but the level of the monsters are:
oblivion knight: 30
doom knight: 24
venom lord: 30
storm caster: 30
looks like the monster that dropped it was a doom knight, which is too low for 4os socket on the crystal sword.
edit: many areas in normal can drop items capable of 4os with larzuk, but theres a reason everyone says cows. theres no room for error at cows. anywhere else unless you know the exact monster that dropped it, theres no guarantee its high enough level