"The Messenger of Allah [SAW] forbade mixing Al-Busr and raisins, and Al-Busr and dried dates, and he said: 'Soak each one of them on its own.'" (Using translation from Nasāʾī 5570)  

سَمِعْتُ أَبَا هُرَيْرَةَ يَقُولُ نَهَى رَسُولُ اللهِ ﷺ أَنْ يُخْلَطَ التَّمْرُ وَالزَّبِيبُ وَالْبُسْرُ وَالتَّمْرُ وَقَالَ انْبِذُوا كُلَّ وَاحِدٍ مِنْهُمَا عَلَى حِدَتِهِ