Importing existing animations with the “attribute ”encountered an issue

I have an animation where a certain bone node has two children, and the animation calls the GameObject's active property to show or hide them. After importing this animation, I received a warning indicating that the m_Active attribute does not exist. I tried adding the m_Active field in the custom properties, and one of the error messages disappeared after re-importing. However, there is still a similar error remaining. When I attempted to add m_Active again in the same way, it prompted that two attributes with the same name cannot be added under the same node. How should I deal with this issue?

PS: When adding a target object to a property, can only one be selected, or can multiple objects be selected simultaneously?