Lifeline AGM and extreme temperatures?

I have seen flooded batteries do it too. It may dawn on you this is a QUALITY issue not a chemistry distinction. Self discharge SHOULD therefore be highest in AGM batteries with the lowest impedance - right? Sorry. Wrong. A battery has fully capable tendencies to eat itself if constructed wrong. An AGM that has a high static discharge is inferior. But just because the battery may hold high static voltage is not a guarantee of good quality. Some fall head-over heels for hyperbole and overly fussy technical recommendations. It's a free decision to manage personal property according to choice. Just remember those thousands of AGM batteries basking in underhood temperatures at voltage values far in excess of float recommendations. Do you see skull and crossbone symbols NOT FOR AUTOMOTIVE USE?