Which coil are you using and at what power setting? I have found that if you are using the upper end of the recommended wattage ranges, you will get a burnt taste, especially if you are using a higher VG juice and chain
vaping or taking extremely long hits.
On my Atlantis 1, I am using the 0.5 ohm coil at 30 watts with a 70VG juice and have no problems with a burnt taste, unless I am chain
vaping (vaping one after another with a 5-10 second break in between vapes and taking a 3-4 second hit) then it will start tasting burnt after the 4th or 5th vape.
On my Atlantis 2 with the 0.3 ohm coil, I'm vaping a 90VG juice and have no problems with a burnt taste, and I am using it at 65 watts. However, I am only taking a 2-3 second hit, since any longer and the vape gets too hot. And when I start chain vaping with this at 65 watts, the tank gets pretty warm to the touch after about 7-8 vapes then I need to put it down and let it cool. I don't get any burnt taste though.