A flaky battery is unpredictable; it’s likely that it will boost “sometimes” but not other times. And that “sometimes” will probably not even be able to be lock

A flaky battery is unpredictable; it’s likely that it will boost “sometimes” but not other times. And that “sometimes” will probably not even be able to be locked down to a simple model of having precise conditions where it works or doesn’t. For example, the battery might be able to boost if the phone is cold, but not if the phone is hot—or vice-versa. It might work to boost for one long boost (i.e. the battery test), but then not be able to do it again for three minutes after that. It might take several tries (pulses of demand) to get it going, and then work. Etc. Think of a flaky battery like an engine with a bad/clogged carburetor. What pattern of starts does it take to get the engine to turn over? Without seeing the gunk inside the carburetor and doing a turbulent-flow model, you can’t really say.