Urengaitik does not exist, in any case it would be; Urengatik, which also does not exist. As "gatik" is a composition in a multitude of words, it is impossible to give an answer. . . It can be "uratik", "urarik", "uretatik". . . Even , you could have understood something else and be; "horregatik" and many more, but never "gaitik" which is just a way in which it is usually pronounced more than anything by speed of the language and those things