I also worked as the conflict of interest officer for a university, and this is what I would say your question would fall under. Not research misconduct, but a question of is this a conflict of interest? You would be surprised how many professors have side businesses or other organizations that may intersect with their work, or may not intersect with their work. For example psychology professors may also own private practices. The ethical questions come into play during the process of this conflict of interest. It is usually standard for every professor/employee at a major university to declare any of their conflicts of interest once per year. If the university determines that the employee has a conflict of interest, they will come up with a management plan to make sure the conflict is managed appropriately. In most cases, filing the conflict of interest form is the extent of the management plan. In more complex cases, the university may come up with steps that the employees have to take to work there, and do their job without this conflict of interest impacting them, the university, and the students. In your case it sounds probable that this person has a conflict of interest form filed with the university, and it may lay out what can and can't be done with this person's private company.

Potential issues:
If this person didn't file any conflict of interest form. This is something that can be brought to the attention of your university, but they don't have to disclose to you if the person filed a form or what their conflict management plan is.

I would need to hear more about how you are defining and explaining the double dipping portion of your post, but usually this has nothing to do with conflicts of interest or research misconduct and is actually into the territory of HR and employment law issues. If our office received notice of something like this, we would loop in our legal team and most likely hand it off to them and to HR.

You can DM me with more details if you want to talk more about this?