Thank you for your question. There certainly was corruption of the hadith from the Prophet (saw) and Imams (as) even during their lifetimes and so at times the companions of the Imams (as) would check hadith that they did not recognise with the Imams themselves. Since the time of the ghayba one of the most important concerns of scholarship is to deal with the corpus of hadith and define benchmarks for deciphering authentic traditions from less authentic ones. There are a number of methodologies for doing that, some of which are quite technical but are discussed in the sciences of usul, hadith and rijal.
May you always be successful