這問句很難看得懂，它的文法是否錯了？

If we replace the question mark with a period, then this sentence will be gramatically correct, and should be easier to understand as well. As a statement, rather then a question, this sentence has the same meaning as:
"Her school grades is the issue".她的學業成績是問題所在。 The implication is that she didn't get good grades in her school report card, and that is an issue to be dealt with..

這句多來自口語的問句，全句可分兩部份，第一 What is at issue. 第二is her school grades?

What is at issue 解= 什麽在討論中。is her school grades? 解=是她的學業成績嗎？

如果單論文法，這句當然是錯啦，句子中間缺少了一個 Conjunction連接詞，我們只可當 "is her school grades" 是一句 Clause 子句看，而這子句稳藏了一個"comma" 逗號 或 Conjunction連接詞而矣！

What is at issue is her school grades?=有问题的是学习成绩？ ok? 如你不懂,可再問.

At issue=argument issues
--------------controversy topic
--------------question on her subjects of exam.result
--------------=good grades on school subjects.
--------------means her grades.