Not looking to trash brands but has anyone had one battery in your 36 volt trolling motors chain go bad when all three were bought same time and less than a year old?

Yes.

They are all slightly different. And all have to fail at one point during their lifespan.

Right now, I have 3 April 2017 batteries and one June 2015 battery. (<<< still works fine on my electronics)

I have a 24V trolling motor and had one of the two batteries go bad and they were exactly the same and purchased on the same day. The second battery is still going strong. The bad one was exchanged under warranty. The batteries are 10 months old.

Most brands are the same Battery just different stickers

Most are either made by Johnson Controls or East Penn.