How to handle one doctoral supervisor being unhappy over a doctoral student's preference for the other supervisor?
While there are lots of ways to go about this, one is to have your primary (academic) advisor intervene in some way with the other person. The industrial person needs to understand that your doctoral research comes first and shouldn't be compromised.
But, this assumes a few things that might not be true. First is that the industrial person can't put a veto on your work somehow. But better that the two &quot;senior&quot; people have a discussion about priorities than you fighting with a more senior person.
But analyze the situation before taking any advice, including this one. It is you that is at risk.
And, for what it's worth, your preference for the academic advisor is certainly appropriate.