Are Objective Characters as blind to the Problem in their Throughline as the Main Character is? If not, then how come they don't simply solve the Issue at hand (with the appropriate Solution).
No and yes.
Objective characters are not a single group of characters working in concert with one another. There are many factions, as well as many varied functions performed by the various characters. They never all have the same agenda. In fact, as much as the protagonist works toward resolving the OS Problem, the antagonist works against its resolution.
The bulk of the objective characters are not aware of the Overall Story Problem and OS Solution until the last act of the story. Some may never be aware of them, even after the story is over. They might see them but not recognize them for their importance. Others may never be aware of the OS Problem and Solution, seeing only the OS Symptom and OS Response.
There will be one or two or more objective characters peppered in the story that can see what is going on, or at least partially so. They provide the voice drowned out by the crowd of other characters that gives insight into the story mechanisms that drive the Overall Story throughline. Sometimes it is the protagonist that does this (e.g. Atticus Finch in To Kill A Mockingbird), sometimes the Guardian character, the Antagonist, or a combination of characters (e.g. Obi-Wan and Princess Leia each have incomplete, privileged knowledge about what is really going on in Star Wars: A New Hope).
Even then, these characters may not know about the OS Problem and Solution until later on in the story. Like the Main Character development, it is not a matter of being all or nothing, but a matter of WHEN they know -- or suspect -- what is causing the troubles. Unlike the Main Character development, the Overall Story throughline present the logistical problem to be solved. Instead of the layers of justifications blinding the MC from the source of his troubles, there is a Story Goal in the OS throughline, with Requirements, Prerequisites, Preconditions and more to wade through in order to achieve the Story Goal while resolving the OS Problem.
Lastly, there is the matter of when the AUDIENCE finds out about the OS problem and solution. That is mostly a matter of storyweaving -- controlling WHEN essential information about the storyform is revealed to the audience. There may be a difference between when the characters know, and when we, the audience, know, and when we know THEY know. Fortunately, it's up to us as authors to make those distinctions as we see fit.
I'm creating a story around a protagonist who is manipulating/deceiving his friends. They think they are helping him, but are really being put into uncomfortable situations by the protagonist on purpose...I'm pleased with the Story Goal (Playing A Role) and most of the storyform. However, though I've read and re-read the Context and Examples for "Proven," I cannot wrap my head around its use in this story. The examples seem to be very literal; a problem with something that is either proven or unproven, like in court. But this is a story about trust and manipulation. In fact, my McKee-esque Controlling Idea is "Relationships are destroyed when your trust is betrayed by a loved one." That feels right, but I absolutely cannot relate it to a problem of "Proven" for the life of me...Any insight will be of tremendous help.
OK, let's break it down into components.
First, we're dealing with the Overall Story so it's going to be the "big picture" view of the goings-on. This involves all the OS characters (to varying degrees).
We have an OS Throughline of Manipulation (Psychology). This is the area of mind games, deceit, mistaken identities, mistaken attributions, etc.
The OS Concern is Playing A Role. This fits well into the throughline topics above. People concerned with playing roles which cause or are in reaction to conflict.
The OS Issue of Knowledge means we're dealing with thematic materials concerning what is known, unknown, knowable, unknowable, and all things related to familiar patterns taken for fact.
The OS Problem creates conflict by definition. The OS Problem of Proven means conflict is created from too much proof, or too little proof, or the acceptance of something as Proven, or the non-acceptance of something as Proven, etc. The point is, the existence or exploration of Proof (or something proven) is the source of conflict. So, if you have an erroneous Proof it will create trouble.
Proven itself is not necessarily problematic. You must find a context in which it IS problematic.
Here's an example tying in the four levels of this OS throughline with Proven as a problem:
Proctor Jones is an evil man who wants complete control of his 17th century township. The only problem is the goody-two-shoes vicar. To get rid of the vicar, he decides to manipulate the town elders by creating a "witch scare" and blaming it on the vicar (MANIPULATION).
He convinces a local woman to pretend like she has been possessed by the Devil (Playing a Role). The woman blames the possession on the vicar. Proctor Jones suggests bringing in someone familiar with possession, an expert in arcane knowledge, who is unknown to all but Proctor Jones (OS Issue of KNOWLEDGE).
The expert suggests that the vicar is the cause of the woman's possession. The town elders, with the subtle guidence of Proctor Jones, decide the vicar must be stoned unless he can prove his innocence (OS Problem of PROVEN).
To make things worse for the vicar, the "expert" points to several moles and scars on the vicars body as "proof" of the vicar's evil pact with the Devil. Since there is no proof the vicar can give to prove his innocence, it is unlikely he will survive, unless.....
This technique works well. Try it on your own particular story.