The strategy guide is wrong!

[SeeDRankLou]

Quote from the strategy guide:

Ch 5, Zanarkand
"Zanarkand is one of the easiest areas to visit at the start of Chapter 5. Also, if you gave the sphere to New Yevon during Chapter 2, it's important that you speak to Isaaru at Zanarkand before heading to Bevelle."

So this scene with Isaaru will only happen if you gave the Awesome Sphere to New Yevon.

But you are right about the other part:
Ch 5, Bevelle
"Move to the entrance of the temple. If you signed on with New Yevon, you'll receive an Episode Complete! However, if you gave the sphere to the Youth League, you'll only witness the final scene with Maroda."

This is incorrect, and what it should say is that if you sided with New Yevon and didn't talk to Isaaru in Zanarkand then you will only get the final scene with Maroda.

If's funny though, later in the 100% Completion Guide, where it tells you to side with the Youth League in Ch 2:

Ch 5
Bevelle, +1.8%
-Episode Complete
-Inside Via Infinito....(blah blah blah)

The writer of this one did make a few slight errors.