This question came up last night. If a spellcaster casts a spell with the Persistent Spell metamagic feat applied, because it requires a second saving throw if the first one succeeds, would it (or should it) also allow a second caster level check to beat spell resistance if the first one fails?
The SR check should only be made once, but I would understand if a DM did it twice to give the player a second chance if the SR was not passed the first time, however the same would apply for monsters also, so it is fair either way to me.
Good question, but I believe that NO:
Persistent spell specifically only allows 2 Saves, there is still just one CL check for SR.
Specifically, check the last line:
¨Spells that do not require a saving throw to resist or lessen the spell's effect do not benefit from this feat.¨
Alot of spells that don`t require a Save ARE subject to SR, but they specifically don`t receive any benefit.
I agree with Wraithstrike, it would be a reasonable house-rule (non-PFS) to allow something like this. I would only consider allowing one re-roll, either Saving Throw OR SR, not one of each though. There`s other ways to get Savign Throw re-rolls or SR buffs.