Cigar flavor - altered by flame heat or butane question

First off, I know this is a pipe forum but I've asked this in a few other forums first without much luck so I'm trying here hoping someone here can help me out...
I've been smoking Cafe Creme's since around 2003, about three or four a week back when I used to smoke cigarettes. Now that I've quit I smoke 2 or 3 a day although I try to limit it to 1. Over the years I've mostly used bic or cricket lighters and sometimes I would pick up a cheap novelty lighter and use it until it failed.
I recently purchased a Dunhill Rollagas (using Dunhill butane)and immediately I noticed a difference in flavor. Harsher on my tongue and throat and a slightly altered flavor of the cigarillo, notably being a little lighter and I notice a lingering taste on my tongue as the cigar flavor disappears. Initially I thought it was all in my head but I've done a few comparisons now lighting cigars one after another with both the rollagas and cricket lighter. The difference definitely exists.
It's not a scientific measure but I can see no difference in color of the flame used in the disposable lighter I use normally, to indicate a difference in temperature. No strong odor from the lighter either when I smell the needle/nozzle while it's open. Short of tasting the butane, I've run out of ideas to try and identify the source of the flavor. Everything else is the same, the way I light the cigars, distance to the flame, how hard a take a puff, storage of the cigar etc...

I've never had problems with using disposable lighters. I have noticed a few times with different lighters a slight difference in flavor but never anything as noticeable as with my new Rollagas.
First thing tomorrow I'm going out to buy some $%&?*@! matches.

Thanks. I've tried not touching the cigar with the flame, even an inch or two away and almost burned part of my beard off because I couldn't see the flame, but the taste is still there.
I've given myself a severe stomach ache lighting and relighting these cigars with different disposable lighters I have around the house, and sniffing the gas like some junkie trying to compare the differences in how they smell. So far I can tell subtle differences in flavor lighting up with different disposable lighters, the worst and most noticeable is still the from the Rollags.
At this point I'm pretty sure it's from the butane, so I'll to find a different brand. One other thing that crossed my mind is that it could be some sort of residue from an adhesive or chemical used in the manufacturing process of the lighter, still in the tank. I don't know if that sounds plausible to any of you, I did think of it after sniffing gas from the different lighter nozzles and may have been a little light headed at the time.

Hey rothh, it's actually Dunhill butane which is supposed to be one of the better ones available, which is why I assumed the cause of the altered flavor was something else. I didn't think a triple refined fuel would affect the flavor, or maybe it's just that I'm used to how the cricket lighter alters the flavor of this particular cigar...
I did think of a less toxic way of finding out whether butane is in fact the cause of the flavor or not. I found an old BBQ lighter and used it to light a cigar, then I purged it and filled it with the Dunhill butane which resulted in a different flavor, and it's pretty much the same as on the Rollagas. I'm not yet 100% certain as I've only tried it once.
As far as butane goes, I have two other options, Zippo or Ronson. There is another local brand Alliter which has "refined in the usa" written on the front. We don't have vector or any other brands so I'll probably just try the zippo or ronson ones.

Hey guys, I've not had a chance to go out and buy some other brands of butane, but I have tried the lighter again on other cigars and experienced the same thing. One other thing I noticed, when I light up with the Rollagas, i experience the unpleasant flavor and harshness but when i put it out and relight with my cricket lighter, most of the harshness seems to have disappeared.