(a) Stereoscopic observation overview with AIA 171 Å and FSI 174 Å, where the angle between Solar Orbiter and SDO was 101°. (b) and (c) The filament shown in AIA 171 Å and 304 Å, displaying a slightly twisted structure with a notable brightening in the central part (indicated by a white box). (d) HMI LOS magnetogram showing the upper section of the filament rooted near a sunspot in positive polarity region. The black box indicates the region corresponding to the brightening in panels (b) and (c), with an evident emerging positive polarity. For the visualisation of the HMI magnetogram, we employed a symmetric logarithmic normalisation (SymLogNorm with linthresh = 50, vmin=-750 G, vmax = 750 G). Red and blue colours represent positive and negative polarities, respectively.