Flowblade rendering audio issue

I am trying to make an hour long film out of scenes I have already created on flowblade but every time I try to render it partway through the audio goes out of order and audio scenes from later start overlooking current scenes so there are 2 audio playing at the same time. At the moment I am putting 3 videos together. I have been using flowblade for several years and never had this problem before. I have even started it all again put still have the same problem. I am not a computer specialist or a video editor specialist but am just trying to do a video for children that I teach. At the moment I am at my wits end and would just be grateful if someone could help me.