"If a woman is married off by two guardians, then the first marriage is the one that counts, and if a man sells something to two men, it belongs to the first one." (Using translation from Nasāʾī 4682)
عَنِ النَّبِيِّ ﷺ وَشَكَّ فِيهِ فِي كِتَابِ الْبُيُوعِ فَقَالَ عَنْ عُقْبَةَ أَوْ سَمُرَةَ أَنَّ رَسُولَ اللهِ ﷺ قَالَ أَيُّمَا امْرَأَةٍ زَوَّجَهَا وَلِيَّانِ فَهِيَ لِلْأَوَّلِ مِنْهُمَا وَمَنْ بَاعَ بَيْعًا مِنْ رَجُلَيْنِ فَهُوَ لِلْأَوَّلِ مِنْهُمَا