So, let me start by saying I think this is probably a totally unintended interaction, but I want everyone to consider:
Instigator: enemy squadrons at distance 1 are treated as if they are engaged by 2 additional squadrons, even if they are not currently engaged.
Valen Rudor: While an enemy squadron is engaged with another squadron, it cannot attack you.
So let me ask a simple question:
If Rudor cannot be attacked while the enemy is engaged with another squadron, and a ship cannot be attacked while you are engaged with a non-heavy squadron, does this mean if an enemy squadron is at distance one of both Rudor and Instigator (and no other squadrons), it can't attack anything?
The obvious answer is to intel Rudor, but even so...