All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The scholars differed in opinion in regard to trimming the beard, some disliked it and some permitted it. For instance the Shaafi'ee school hated to take anything from the beard at all.
Imaam, An-Nawawi said: 'The correct opinion is that it is disliked to take anything from beard at all. Instead, one should leave it to grow as it is, as to act in accordance with the Prophetic narration, 'Let your beards grow'.' Nonetheless, some other scholars permitted taking from the beard what exceeds the length of a fist, and this is the view of the Hanbali school. Al-Mardaawi said: 'It is not disliked to take from the beard what exceeds the length of a fist.' However, the Maaliki school are of the view that it is permitted to take from the beard without any restrictions. Abu Al-Hassan said: 'There is no harm in trimming the beard if it is very long, and it is established that there is no limit in taking from it.'
Therefore, it becomes clear that taking more than a fist's length is a matter of difference of opinion among the scholars, and it might be that the scholars who do that are of the view that this is permissible.
Allaah Knows best.