Since the most recent patch, charm pets are unable to have any more than 10 buff and debuffs on them at any one time. Test subject: a venomous viper in Feerrott, the Dream. Spells: Edict of Tashan Rk. III Tashan's Lingering Cry VII Marvel's Command Rk. II Night's Perpetual Terror Rk. III Night's Terror Feedback Wondrous Rapidity Invigorated Minion Rk. III Overwhelming Splendor Umbra As you can see, attempting to cast Intellectual Superiority, and then Scrying Visions, both failed to land due to a venomous viper being bufflocked. Test subject: a dark whelp in Maiden's Eye (Terror of Luclin zone) Spells: Edict of Tashan Rk. III Tashan's Lingering Cry VII Marvel's Command Rk. II Night's Perpetual Terror Rk. III Night's Terror Intellectual Superiority Wondrous Rapidity Overwhelming Splendor Feedback Invigorated Minion Rk. III On attempting to cast an 11th buff, Umbra, again, the pet is already bufflocked. The buff order was different to illustrate that it is not spell-specific, but rather the number of buffs. The persistent enchanter pet, summoned by Constance's Animation Rk. III, is not affected by this: so clearly it's just a charm pet template issue.