`Input<string>` and `Input<Object>` cannot co-exists in the package

We have created a sample package called TestInput which contains only two Test steps (InputObjectStep.cs and InputStringStep.cs)

InputObjectStep contains one property:
public Input<object> inputObject { get; set; }

InputStringStep contains one property:
public Input<string> inputString { get; set; }

When we try to add both test steps we get a serialization bug.

Also when we try to run the Test we get another bug:

Reported by @justinci