Is it permissible for some imams in the Tarawih prayer to combine four or more rak'ahs in one taslimah without sitting between the two rak'ahs, and is there any basis for that in Sharia?

This action is impermissible, rather, it is makruh (disliked) or haram (forbidden) according to most scholars, due to the Prophet’s (peace be upon him) saying: "The night prayer is two by two." And due to what was authentically reported from Aisha (may Allah be pleased with her) that the Prophet (peace be upon him) used to pray eleven rak'ahs at night, performing taslim after every two, and concluding with one witr. As for Aisha’s hadith: "He used to pray four rak'ahs at night, and do not ask about their beauty and length, then he would pray four," her intention was that he would perform taslim after every two rak'ahs, and not pray the four continuously with a single taslim.