Currently, the following heroes have bugs regarding Get/Set Ammo and Get/Set Max Ammo actions and will return 0 for any clip provided:
- Mauga
- Venture
- Kiriko
- Lifeweaver
There is no known workaround for this time.
However, Bastion's ammo count in Assault mode (clip 1) is still 300 by default, it simply does not deplete. This is not a bug, and can be used to trigger his reload animation, which is currently not possible without using workshop scripts.