It has pretty much been proven that no matter how well you care for your cartomizer, the burning process begins immediately to a certain extent. There is anecdotal evidence that the popping is indeed burning material. One of the members in the above link took some filler material and put an open flame to it, the member reported that it made the same noises that can be heard when vaping.
As for how an adapter will impact the rate of burning, there is no issue here as long as you are indeed using an ADAPTER.
If by an "adapter" you mean a passthrough and not something that converts the screw in bit (threads) then yes, possibly. A passthough may or may not be delivering 5 volts to the cartomizer causing it to reach a higher temperature.
Personally, I use these cartomizers on a 5 volt regulated box mod that I made myself and I love them. There is currently a new type of cartomizer being sold market as the Edition 2 or E2. In the description the manufacturer states that it contains no cotton filler, these may have different properties in regards to burning, or lack thereof. I haven't managed to get my hands on any of them so I can't tell you either way. There are some reviews and concerns about them here on the forums. There is a coop starting for these at this link ( You may need to be in the "Pay it forward" social group to get to the link)
E2 cartomizer PIF CoOp