The biggest example of this is the 20 metre zero tackle restart. It was brought in to stop teams kicking dead on purpose to take the return by the likes of Jarryd Hayne and Billy Slater out of the game. But it also acts as an incentive against normal fifth tackle options: kicking a grubber for a winger who can't quite ground it is obviously not a negative play, yet it has the same outcome as booting dead from half way. Worse, there are completely peverse outcomes: if a winger dives for the line and drops it in play, restart with a first tackle at 10m. If he drops it in goal, zero tackles 20m.
It would be really, really easy to resolve, too. Just say that the zero tackle rule applies to any kick taken from outside a certain range - say, 30m. Or kicks that go dead untouched, or dead through the back of the in goal. But the NRL has no interest in making this 'fair' - they just want as many sets as possible starting in good field position, thus increasing the chance of points. The best thing about this rule is that it gives teams a leg up right at the handover, so it's relatively low impact.
It will backfire eventually. You already see teams dying with the ball on the fifth rather than risking a 20m restart, especially at the end of games when protecting a lead - when they judge that the risk of a 20m restart is greater than the pay off of possibly scoring. And in golden point, teams often turn down long range field goals because the relatively low chance of scoring isn't worth the better opportunity the opposition will likely get from a 20m zero tackle restart. Sooner or later there will be a period of time in which goal line defence has the upper hand, and teams won't want to roll the dice on the last unless desperate or with a gigantic overlap etc. But then the NRL will just change the rules again.