There are two Sujud in Salah. I have heard that one relates to Allah's command to all angels including Iblees and the other one relates to thanking by all angels that they did not disobey Allah as Iblees did.
Is it true?
IF anyone makes any claim, then he has to bring its proof that if it is present in Quran or Hadith. During my study of islam, i never came across anything like that.
Also, you should note one thing that not every question deserves or needs an answer. i mean in this case, the MAIN motive of Salah is to worship Allah and those actions have to be according to Sunnah. As long as you are doing this, that is enough. So even if you are not aware of why certain actin is done, still your main purpose of Salah is fulfilled, so nothing to worry about.
As a conclusion, i would say that you should not believe in such saying that certain Sajda is for certain reason, Unless there is an evidence for it. Just pay attention to the important part of Salah, ignoring such issues.
May Allah accept our Ibadah and indeed, Allah knows the best