"the result of the play is technically a TD"
Although, ""the result of the play (satisfies the requirements necessary to constitute a TD, and may well be) is technically a TD", does it actually "score" a TD when the play includes a live ball foul, until the adjudication of the penalty and the effect that decision may have on the play, determine
whether a TD will be "scored", or not? An official
NOT observing the actual penalty, may signal TD based on his observation of the scoring action, but the official observing, and calling, the violation would be aware that the legitimacy of the score is in doubt, until the penalty decision is concluded, and as suggested simply terminating the action until a final conclusion is determined, by a TO signal, seems best to minimize any subsequent confusion.
When circumstances create conflicting signals discussions between officials, which may or may not , involve the Referee seems best to avoid confusion, until a confirming,
single signal from the Referee clarifies the conclusion.