Sadly, yes, flavors can kill a coil very fast, especially at higher wattages. Were you using different juice profiles prior to your coils getting burned? Different coils? It's been going on a month? I'd be sure to also take apart EVERYTHING you can from your tank, as well as your mod, and check the 510 pin to make sure nothing juicewise got down in there, as well as maybe wiping off the battery ports. If you've had a burnt taste that long, there MAY be some gunk lodged somewhere in your tank or mod that you don't know about, that's causing the taste (apologies if you have already tried this).
Also, have you tried the tank on a different mod? I could see circumstance where your mod might be having electrical issues and giving you poor readings on your coil, or even firing at a different wattage than you THINK it is, so if you have a friend that you could try your tank on their mod, that might help.... Or, take the sucker to a decent brick and mortar if you can find one with knowledgeable employees close by, and they may be able to help. That's kinda the most that I can think of? You may also have gotten a box of bad coils, it does happen, so trying a fresh stash might be in order....
Best of luck, I hope you are able to sort out your difficulties.
Anna