fenix tk21 having a problem

Hey guys, Ive had my tk21 for about 2+ years now and recently Ive been having some problems with it. It will not stay in turbo for more than 5 seconds (a problem Ive been having for about 6 months now) and recently will not stay in high (drops to medium after about 30 seconds to a minute) I use AW 18650's with a pila charger and have tried numerous different batteries all with the same problem. I have tried cleaning it to no avail. Im not real savy with fixing lights, anyone have a similar problem or suggestion on how to fix this.
Thanks in advance!

The symptoms you describe all point to the batteries.

i thought the same thing but its doing it with ALL the batteries and started doing it with all of them at the same time thats the reason i dont think its the batteries. For them to all go at the same exact time would be weird no?

Yes, I realize that.
Only other think I would think could be the problem is a bad connection...