With Panache! at Swashbuckler level 8, you are supposed to receive a bonus to all social skills (Bluff, Intimidate, Leadership, Perform) equal to the higher of your intelligence or charisma modifiers. That doesn't happen (for Intelligence, at least).
Steps to reproduce the Bug:
Have a Swashbuckler with a +8 INT modifier
Expected Result:
Get +8 to Bluff, Intimidate, Leadership, Perform
Actual Result:
Get none of the above bonuses.
Screenshot(s)
From the Wiki:

Additional Information/Notes
Character has a +0 modifier to Charisma, if that matters.
Character has a hard INT of 18 (so +4).
Platform: PC
Tested on the PGCC server.