No, most likely your CUET UG result will not be affected if you wrote the wrong mother's name in the attendance sheet.The primary purpose of the attendance sheet is to verify your presence during the exam. The information on your main answer sheet,  where you fill in details like your name, roll number, and exam details, holds more weight for result processing.

https://university.careers360.com/download/sample-papers/cuet-ug-model-question-paper

I hope it helps!