The key is always to determine what duties the person was performing at the time of the decision. That's what must be done. Whenever a person has both statuses, meaning that they're subject to both the conflict of interest code for MPs and the Conflict of Interest Act, it's necessary to determine whether the person was acting as an MP or a minister at the time of the decision. If the person was acting as a minister, the act applies to the situation. If the person was simply acting as an MP, the code applies. Each situation must be reviewed in this manner.
In the case of the WE Charity, Mr. Morneau and Mr. Trudeau were obviously acting as ministers, not as MPs for a constituency.