Currently there's no validation within the animation attribute container that bone ids are valid. This means that client/game code can add attributes with invalid bone ids into the container and th ...
This does not occur in 4.17.2 at CL 3658906 ...
It's 100% reproducable ...
I've only had this happen once. ...
When the user tries to export the Skeletal Mesh of TwinBlast (a paragon character that can be purchased off the marketplace) in 4.23. As of the time of logging this bug it is not supported in 4.23, ...