I saw the Messenger ﷺ perform ablution. He had a Qutri turban. He inserted his hand beneath the turban and wiped over the forelock, and did not untie the turban. (Using translation from Abū Dāʾūd 147)
رَأَيْتُ رَسُولَ اللهِ ﷺ يَتَوَضَّأُ وَعَلَيْهِ عِمَامَةٌ قَطَرِيَّةٌ فَأَدْخَلَ يَدَيْهِ مِنْ تَحْتِ الْعِمَامَةِ فَمَسَحَ مُقَدَّمَ رَأْسِهِ وَلَمْ يَنْقُضِ الْعِمَامَةَ