Yveltal with "Fright Night" Ability knocks out Wobbuffet with the "Bide Barricade" Ability which was turning "Fright Night" off. Does Exp. Share on the Benched Pokemon behind Wobbuffet work?
Yes, since Wobbuffet was not yet in the Discard Pile, Fright Night remains off and Exp. Share works.
Source: TPCi Rules Team (2017-04-20)

Relevant cards

Note: All applicable cards may not be listed below.
XY4_36
XY5_128
XY8_94