Fiery Spell Weaver Quarterstaff Bug

[Sanduru]

I'm playing a sorcerer and got the Fiery Spell Weaver Quarterstaff, but it's bonuses don't seem to work. The description says: "This +5 flaming burst quarterstaff grants its wearer a +1 bonus to CL, +4 bonus on checks made to overcome spell resistance and a +15 competence bonus on Use Magic Device skill checks." but when I equip it and look at the stats in the Spellbook it doesn't seem to update the Caster Level and add the +4 bonus to Spell Resistance check. It does give me the +15 bonus to the Use Device skill though.

The problem is that I also have the Quarterstaff of the War Mage that DOES add the +4 bonus to Spell Resistance check. Am I missing something or is this a Bug? Has anyone got this problem?