bards do not add cha to spell save DC on tasha's hideous laughter

(solved, not a bug)bards do not add cha to spell save DC on tasha's hideous laughter

I have a bard, his stats are:
STR 11
DEX 21
CON 20
INT 15
WIS 10
CHA 25
(he has a bunch of +6 to stat items).
I noticed tasha's hideous laughter never works. So I looked at it and I saw that the DC to resist it is 14.
It should be 18=10+1 spell level on bard list+7 cha mod... i think it works off of the "wizard" casting and counts it as 10+2 spell level (on wizard list)+2 int mod

EDIT: It seems that it was simply a +4 racial bonus if type differs from that of the of caster. it is implemented by -4 to DC rather then +4 to their roll. (And giants are not humanoid)