Is it permissible to disregard an authentic hadith that has no defect and not act upon it, and what is the meaning and ruling of some madhhabs' saying: "A hadith that is not acted upon"?

Submission to the Sunnah is obligatory, and the statement of the Messenger (peace be upon him) must be given precedence over the statement of anyone else. No one is permitted to take a prophetic text without gathering the rest of the evidence, for there may be defects in an authentic hadith, such as abrogation (naskh), specification of a general text (takhsis al-’amm), or consensus (ijma’) not to act upon it. The abandonment of عمل by the Salaf of an authentic hadith indicates knowledge they possessed that it should not be acted upon, for later generations cannot understand what the Companions and Tabi'un did not understand. It is not permissible to act upon an authentic hadith if all the imams of ijtihad have abandoned it.