If that is true, why? I can think of four possible reasons:
1) Is it because the simulation was designed in such a way that it leaves its inhabitants clues that reveal the true nature of the universe? This lets them figure out the truth once their society and knowledge become sufficiently advanced.
2) That it's impossible to simulate a real universe? This would imply any sufficiently advanced society will be able to detect that they do in fact live within a simulation.
3) That the creators made a mistake and it's not a fundamental limitation. It's simply an error made by whatever civilisation created this simulation, they messed something up.
4) That it's possible to create a perfect simulation, but for some reason they decided to make a simulation that used less resources and this brings errors or the need of hacks to get it working. Now we might be exploring these hacks.
It's likely simulation would be ended if we beat its purpose by hacking it. End of the world coming?