Tolerance is a perk-level version of Resistant found on page 24 of GURPS Psionic Powers, this is +3 vs a single psionic ability. An example is given of Confuse, which is a specific Affliction with the psionic (ergokinesis) power modifier.
This basically means that "a single ability" is a "rare".
"all psionics" is "very common" so "one power" is probably "common".
"occasional" would be unclear