I think I know why this happens...
HyperPad may see this as an intent of the object itself since the object is in the tag's group. Similiarly to using the loop behaviors to iliterate each object, it does it to only one object at a time.
In this case, the collision behavior will activate the following events because of each object that is collided within it's tag, it will have the intent of that object that it has collided to.
For example, two objects are going to be used. Object 2 is in a group. Object 1 has a behavior where when it collides within that group to change the color of it's tag. If object 1 collided with object 2 with the tag, it will change the color of object 2 as object 2 was the intent of this case.
This may be confusing, but I learned from experimenting with tags and looping properties.