Embedded systems are based on specialized hardware designed and manufactured for a particular use case. This implies that at the time that the software for the embedded system is being developed, its hardware is not yet stable and well tested. When software developers encounter an error in their code behavior, it does not necessarily mean there is a software bug but it might be a result of incorrectly working hardware.

It is hard to triage these kinds of problems. They require knowledge, intuition, and sometimes the use of an oscilloscope to narrow the root cause of an issue down to hardware.