I know that Sombra can hack Bastion when he's in turret mode and it will change him back to sentry mode, but what happens if he's in tank mode for his ult? Does it make a difference if Sombra uses her ult compared to her normal hack ability?
Bastion will stay in his ultimate tank mode until the timer on that runs out or he's killed (or some other character's ability is used that can bring him out of tank mode). It doesn't matter if Sombra uses her hack ability or her ultimate. I tested this with a friend in a custom match after seeing a PotG of Bastion ulting, followed by an enemy Sombra ulting to try and shut him down. It didn't go so well for the Sombra.