I have a specific question about this FAQ through example.
The FAQ states that you cannot apply bonuses from different sources that apply the same ability bonus; for instance, you could not add your Charisma to a Save twice using the Paladin's Divine Grace and Swashbuckler's Charmed Life- only one instance of +CHA would work.
However, the FAQ seems to specify specifically adding it as two bonuses. My question is are you able to have a (ability) based (calculation) and also add (ability) as a bonus.
For instance, could you use Weapon Finesse with a finesse-able Trip Weapon or Agile Maneuvers to have a DEX based CMB and also add DEX as a bonus to Trip from the feat Fury's Fall?
There may be other examples, but that's the one that comes to mind. Citation preferred.
Best Answer
What you describe as base is still defined as a bonus under the rules. So the answer is no, you cannot. Your example is clear when it says that both abilities are adding the dex modifier as a bonus on your CMD
Though they could be argued to be considered different sources being two different feats, the source of the bonus is your dexterity ability, not the feats. The bonus is typed as a Dexterity bonus, and as such, can't stack with itself.
However, there are specific abilities that allow you to add the same ability modifier bonus twice. Those abilities are exceptions to the rule clarified on the FAQ. Usually, the type of the bonus must be different so it's considered another source.
Examples: