2. A person who has mastered a high level of expertise in a subject, notion on field.

Completely different definition. Dawn can refer to both a time of day and dish soap, but they are not interchangeable definitions.

> PROFESSIONAL MISCONDUCT 'Behavior different from what is prescribed in the moral, ethical and professional code of conduct'

For example only uses definition 1.

But when an individual says that they are a "professional", they could easily be using either definition, and still be using the word correctly. The OP said "Software engineers don't understand they're not professionals..." as if only the first definition was correct.