2013 Hyosung GT650R slow start is there a fixable problem

I have a GT650R with 6300 miles (hasn’t been ridden much) and for some reason it has a slow start. It has always started when supposed to but has basically had this issue since new in 2013. The battery has been replaced at least 3 times, the latest is 8 months old. Every time I install a new battery the start-up is fine for a while and then it eventually starts the slow crank issue. I have used YUASA YTX 14BS in the past, this time I installed a XTREME XTAX14-BS AGM battery. The bike has always been running and has never died, it just has the slow start-up, and I would like to know why other than that it has been good when ridden. Hopefully someone else out there has had this and was able to fix the problem.