I'm fairly certain my laptop battery is dying.
Which isn't much of a WTF on its own; after all, the poor thing is a good 5 years old at this point. It's the way it's doing it that's funky.
Sure, overall battery capacity has been steadily draining over the past few years, but it still reports that it's got a little over half of the design capacity. ...sometimes. Other times, like last night, it decides that it has a capacity of about 5% of design and axes everything about 4 minutes after being unplugged (while still showing a nearly-full battery icon).
Indeed, the battery report doc is... Uhhhh... Quite the reading. Not only is it reporting hilariously low capacity numbers (or was last night, now in the morning it's decided we're back to something operational), it's also reporting that same capacity for every day a couple weeks back (which is absolutely not correct). Also all those readings are apparently indefinite, because they have a start date but no end date. There's also a slightly older reading where it registers the estimated current lifespan as a little over 5 hours (correct, when the battery isn't having one of its "moments"), but on that same line it compares it to an estimated design lifespan of 123 hours and change.
Additionally, the readings from the last time this happened have apparently been "retconned", as it's no longer displaying the same values for that date in the report.
A sprinkling of other fun details in there, like a recent usage rundown showing how much capacity was left when the battery usage stopped, where a few days ago it registered a max charge worth 43,000 mWh and that the usage was stopped with only 1327% of that remaining.