that nickel or stainless could be any concern is baffling. of all the metals, they're among the best, handling 1000°F or more without problem. i can try to measure the exact mesh temperature, but i really think it will be hard to get the area above 200°F, and this feels ridiculous. i'd be interested to know a safer material to grip the bowl in place. most pens just use glue in there.
yellow material indicating it's medical grade is stunningly weird as well. or maybe i have something new to learn here (?). not that yellow ceramic is bad in any way, but i always found the easiest judge of purity is by whiteness, such as the totally white medical grade ceramics at this
major supplier.
about the battery- 86°F is considered stressful for most lithium batteries, wearing them out more quickly. the damage deepens with a full charge, oddly. i'm hope it was the battery protection circuit that kicked in for your battery but need to ask the manufacturer about it. did your battery come back once it cooled? i'll check back once i learn more.
thank you ~LV