Same here, but I just re-watched and 38 seconds of match time went by from the time Smith may (looked to me like he had the TD) have had a takedown and the action was stopped. No sign of the brick before that. However, if they had thrown the brick and the refs didn't see it wouldn't tOSU coaches be going nuts trying to call attention to the brick? 38 seconds is a long time.
From the rule book:
Rule 3 -- Conduct of Meets and Tournaments
Section 13. Mat-Side Video Review
Art. 9. Coach's Video Review Challenge.
d. If a coach would like to execute a video review challenge, the coach shall immediately throw the foam brick onto the mat away form the wrestling action. Throwing the foam brick officially signifies the coach would like to use a video review to challenge a referee's call on the mat and the request shall not be retracted. The referee will stop the match as quickly as possible, but only when no significant action is taking place, to either conduct the review or allow the third-party reviewer to conduct the review.
The BTN did not show when the brick was thrown. Perhaps Roar or others that were at the match can clarify that. However, as has been mentioned, there was a long scramble after when tOSU thought Smith may have had a TD, and in the end Hall came out of that with a TD. Per the above rules, it would have been a mistake to stop the match for the challenge while the dynamic scramble was taking place, as that was significant action. 38 seconds is a long gap between the possible TD by Smith and the TD by Hall, but the ref shouldn't have stopped the match during the scramble/TD, and it's also unclear when the brick was actually thrown.