Hi again guys

I've been playing around with this carton and cutter and have just come across this little problem. I've unified the central hub of the box so I can fillet the edges but when I do this it seems to be making some sort of elongated fillet along the whole of the plane and more. As I've booled/unified it and there aren't any curves I can't rebuild it just in case this is what I should've done?

Thanks

Lang