Clip clearly shows that Sigma’s shield is behind me, there is no bubble or second shield blocking the hammer, and the shatter’s path should have struck the whole team. If you watch closely, no one on the enemy team is stunned by this shatter.
I can only think there’s something wrong with either:
the way shatter travels down this set of stairs on Hanamura, or
shatter being blockable by Baptiste’s drone (in the instant the drone impacts the ground)