Blight sir, possibly ran into your issue last night. Had a gold with red led regular manual king diamond that didn't hit at all like it should have. It had been charged the previous night, was using a wow carto at 2.2ohms filled with gunslinger 24mg. Hooked it up to the multimeter, voltage output read as 3.71v. Hooked it back up to the slim charger to make sure it had charged and according to it, yes it had. Tested it at off load voltage, said it was at 4.21v, once load was applied again, 3.71v. Spent the next few hours trying to figure out a fix. First move was the press the button 5 times with load repeatedly. Didn't work. Step 2 was to repeat the process without load. Again didn't work. I put the battery back on the charger, waited 5 minutes, then repeated the button pressing again without load. Attatched said carto, fired it, and it read it's expected 4.194v. Have no idea what caused it, and so far it's the only batt that has done it. It's twin hasn't shown this issue through 21 charges so far, this one showed it on it's 18th charge. Can't verify it's a fix or not because I only had one instance of it, and listed all the steps taken because it could be only the last step that caused it to work, or all of them combined. Will keep an eye on the issue and report any further findings as they come...