I don't mind using third party batteries as long as it's a good quality third party battery. I've been using the white Jupio LP-E6N's in my 5D IV and now R5, and I haven't had any issues with them.
Most lithium ion batteries only perform fully after the 3rd charge. Charge up, deplete the battery, charge again and deplete again. Charge again and now the battery has full capacity.
Most lithium ion batteries only perform fully after the 3rd charge. Charge up, deplete the battery, charge again and deplete again. Charge again and now the battery has full capacity. Deplete = discharge until 5% or less.