Incorrect transmission fluid used

Mercon LV is not compatible with Dexron VI and vise versa. I would have the transmission fluid replaced with the proper fluid. You could be asking for problems leaving it in. I would have insisted the dealer change the fluid to the proper fluid when they first made the mistake. They are not likely to correct the issue at no cost to you after 8 months. You won't be able to drain all the fluid due to the torque converter not having a drain plug so the fluid needs to be removed by a machine that can replace fluid on the fly.

Thanks Bob, really appreciate your answer, so I need to flush them all by the use of a machine and replenish with mercon LV,