This question is irrelevant. No one really knows the answer.
What Igor is really saying, is if you want anyone to spend their time helping with this, you need to reproduce on current code. If this was a common problem, it would already be fixed as many others would report something like this. So it is either something due to your older code, or something specific to your environment. Those are difficult to diagnose, and when you are asking people to volunteer their time to help you, they are only going to do that, if it is a reasonable to do and you have done everything to narrow the scope of the problem to something reproduceable by someone else.
My first thought is based on the lack of information provided, but is a common cause of mysterious errors, and that is power issues. How is all of this hardware powered? SBCs are notorious for having poor power supplies and under load have voltage drops that cause mysterious problems (especially with usb devices drawing some of that power).