Process Mapping is a very useful tool that helps make visible the current state of a series of tasks to assist in the improvement of the tasks and the overall process. There are many ways to understand process mapping. One way is to be aware of the common pitfalls in mapping a process.
The most common error is diving into improving the process before you have finished mapping it. Participants will bring up exceptions and errors and want to discuss them. The point is about documenting how the work is currently being done, by the people doing the work, not how the process should be followed.
Note issues identified but leave them for now. Issues can be prioritized ...