The Messenger of Allah [SAW] forbade soaking raisins and dried dates together, and he forbade soaking Al-Busr and dried dates together. (Using translation from Nasāʾī 5556)
أَنَّ رَسُولَ اللهِ ﷺ نَهَى أَنْ يُنْبَذَ الْبُسْرُ وَالتَّمْرُ جَمِيعًا وَالزَّبِيبُ وَالتَّمْرُ جَمِيعًا ؟ قَالَ عَطَاءٌ نَعَمْ