"remain under debate" is a correct and usable phrase in written English.
You can use it to describe a topic or issue that is still being discussed and has not yet been settled. For example, "The legality of abortion laws in the U.S. remains under debate."
However, the mechanisms still remain under debate.
Alternative solutions remain under debate — day and night — in Sol.
For example, the forces that move the atoms, resulting in dramatic resistance changes during switching, remain under debate.
Despite previous phylogenetic studies of on morphological characters, the relationships among the five euglossine genera remain under debate.
Although work on collective intentionality in philosophy, artificial intelligence, and cognitive science has many points of agreement, several key issues remain under debate.
Bills were proposed this year in 16 states to overturn gun bans on college campuses, and remain under debate in a dozen states.Some argue that arming female students will deter rapists.
Indeed, the nervous, muscle or fibroblastic nature of the ICC has remained under debate for more than a century, as has their possible physiological function.
Even before the parliamentary snag, critical components of the bill remained under debate, including the size of the corporate tax cut and whether it would retain any ability for individuals to deduct state and local taxes.
For more than 100 years, the optimal treatment of femoral neck fracture in the elderly patient has remained under debate [3].
The vote left intact a ban on most types of new U.S. investments in South Africa that is part of HR 1460, an anti-apartheid bill that remained under debate.
Where the subspecies separation is not accepted, whether to consider it a subpopulation of the Atlantic or Pacific subspecies remained under debate until 2009, when multiple lines of molecular evidence showed it to represent the westernmost population of the Pacific walrus.
