Dead Heat rules apply if the match results in a draw after extra time. This means that you will receive half of your expected payout as your odds will be halved.
For example,
If you've placed a $50 bet on Melbourne Storm @ 1.85 originally returning $92.5, your return will be halved as there was a Dead Heat which will be $92.5 divide by 2 = Final returns of $46.25.