Do not agree with you about "pure rage expression through the whole dialogue". For the first shocked line - definitely yes. But when he is talking about what he is going to do with Vernon his "serious" expression is more appropriate to me, cause it looks like he is saying it more to himself. This is the closest thing to my idea of this situation when he viciously says through his teeth that he will kill him.
But on the whole, you are right. This scene can be reworked to add more expression through facial expressions. For example, to add a nervous expression to Chester's face when he does not yet know what the conversation is going to be about, but already understands that something serious has happened. And the smiling standard face expression of the MC is also out of place in this emotional scene.
BTW comments here are not the best way to report a bug, Dyne doesn't respond here as often. He somehow collect feedback through google document on patreon, and I also have no idea how to send a bug report without being a patron. So catch an upvote from me. That's all we can do)