In the Lure of the Lost adventure for the F&D beginner game, it makes reference to gaining 5 Conflict lowering a PCs strain threshold by 2, and also mentions gaining strain threshold if Conflict is lowered. I am running this adventure but using the full rules. Do these rules exist in the core rulebook?

Allen

No, they don't. The beginner games for all the three lines (possibly also the TFA beginner game) plays loose and fast with the core rules. Use it or cut it, it's pretty much up to you.

I may have them juat be rules that apply in the temple.

I wouldn't call it "fast and loose" as it pertains to Conflict/Morality. I would call it being appropriate to the purpose of the game.

In one-shot or limited-run games, mechanics like this can be very helpful. The "Step 1 Mechanic" in the Core Rules (Morality in FaD, Obligation in EotE, and Duty in AoR) is designed for campaigns. But in games that are either designed for a handful of sessions or even just one full-length session, especially for new players, they just don't come into play like they were designed to.

The AoR one-shot game Rescue at Glare Peak has some effects that interact with Duty in an interesting way. IIRC, Shadows of a Black Sun had something similar for Obligation. Basically it's just purpose-built mechanics for the adventure at hand. And the purpose of this specific Beginner Game is to give players a taste of Force and Destiny. So you could either drag out the Beginner Game for a dozen sessions to really give your players a sample of that Conflict/Morality mechanic, or you could just let them feel the weight of their decisions in the short term, and then if they get hooked you can expound upon the rules further. They will at once be grateful that they don't get an automatic strain threshold reduction, and also be intrigued as to what kind of character they could develop with the decisions they made in-game.