I observed that when using Entity Command Buffers in Unity 2019.3.0b6, doing any operations with the Command Buffer (add, remove, modify components) to an entity requires removing the [ReadOnly] tag from the CommandBuffer declaration inside a job. My use case is similar to the MousePick from the Physics Sample, in that I use a job to cast a ray from the screen to the Camera far Plane, check if it hits an object I want, and if it does I mark that object with a Selected tag component. Then in another job I apply an impulse to the object and I try to remove the Selected component, however here in the 2nd job I get an error saying that the CommandBuffer should be marked as [ReadOnly]. When I do mark it, I get an error saying that I should remove the [ReadOnly] tag as I execute modifications. This behavior is not visible in 2019.2.8f1 and the buffer works as expected with the [ReadOnly] tag in place Is this some sort of bug?