[Cecil4]

I think you are describing what was originally a force out.

You said "overruns third base". Was that a "reached third" or not?
Reaching third removes the force.
But, where was R2 when tagged? If still past third, then it is not a force, so the run scores.
The way it would have been a force was if R2 never "reached" third or retreated to be between second and third.

If the overrun of third was toward the right side dugout, maybe R2 did not pass third.
Please clarify.