I am not that active on the forum these days, so apologies if this has already been discussed.
I've noticed lately that I will sometimes put a carto on my battery, activate it, and immediately get an overwhelming blast of burnt smoke. This has happened to me several times in the past couple of weeks. The cartos are neither brand-new or old, but are always well-filled. The batteries are not fresh off the charger.
Yesterday, I was vaping away on a carto and started to sense it was going to run dry. I replaced it with another carto that had been used a couple of times already and was about a day old (and well-filled, of course). As soon as I hit the button, I got a whoosh of dry, burnt, smoky taste. Once this happens, the carto is ruined.
The batteries are Riva 510's (eGo clones that put out between 4.2v - 3.7v) and Boge LR cartos. I've been using this setup for months and have only had this problem for the past couple of weeks.
Not only is the taste burnt and smoky, but the volume of vapor is much larger. When this happens, I can hold out my PV, hit the button, and watch the vapor come out of the mouthpiece. This would never happen normally.