From what i have learned through my inquiries, it has to do with the liquid in the bubble light glass tubes. it is a chemical agent known as methylene chloride, which is what creates the bubbles when it is warmed to its boiling point. as long as the liquid is completely contained in the glass tube, with no leaks, it is totally harmless, as it can produce no toxic fumes or vapors. however, methylene chloride, if not tightly secured in a safe container, (such as a bubble light tube) is highly poisonous and potentially lethal if swallowed, inhaled or absorbed through skin contact. I have collected, handled, and used bubbling christmas lights for many years without a single tragic incident. i have even broken a couple and the liquid escaped. but i was very careful not to breath the fumes or allow it to touch my skin before i safely and immediately cleaned up the accident. no harm at all.
All i can figure is that something bad must have happened, (within the past couple of years) such as a serious incident with the lights, triggering a lawsuit, perhaps, which prompted eBay to disallow the lights to be listed on its platform.
I hope this can help with a possible explanation and answer to your question
I hope this helps explain
