Sympathies to OP for hassle. I have to admit, this is an issue I’ve been worriting about too.
I stopped using the £25ish fleabay lights for mtb because a.) the cables were too flimsy (had a few separate at the connectors) and b.) they give absolutely zero warning of impending black-out when the battery runs down, which is ‘interesting’ at best.
However, we still use the cheap lights as head torches for walking the dogs, plus, I also have heard the odd story of combustion for some of the more reputable makes. As a rule, I don;t charge anything overnight, but out of necessity, often leave stuff charging and unattended.
Edit: I see the price has now dropped to £15 for the lights – the one’s the OP links to look identical to ours.