Chant of Battle Stacking
 

I hope this isn't a double post, i'm sorry if it has already been addressed.

Since the last patch Chant of Battle no longer stacks with Guardian Rhythms. GR is currently overwriting CoB.

CoB adds > STR, DEX, AC
GR adds > AC, MR

CoB currently stacks (and is not over written) with other AC adding songs, including:

Jonthan's Whistling Warsong
Elemental Rhythms
Purifying Rhythms
Psalm of Mystic Shielding
Psalm of Warmth
Psalm of Cooling
Psalm of Vitality
Psalm of Purity
Vilia's Verses of Celerity
Niv's Harmonic

CoB had stacked with Guardian Rhythms in the past, so I'm not sure why it changed.