naturally, it began again after waking from sleep. that’s why it’s so darn tiresome diagnosing it, you never know if the tweak you’ve made has any effect, sometimes it works for hours, sometimes it freaks out after seconds.
if the battery is the culprit, shouldn’t it stop being a problem when running the device on external power? it’s not like it’s constantly charging the battery and simultaneously draining it; at least, no laptop I know of does that. and if the display cable is faulty, then it should also have those flickers when running it without battery. that never happens.