[Al Skierkiewicz]

I wrote this this morning but the internet connection broke at the hotel. Posting now at home.

The MK battery and the Enersys/Yuasa/Genesis battery this year are both AGM batteries designs. If the battery came off the charger at 10.25 volts, you likely had a dead cell already. If the same battery coming off the charger was 8 volts under load, one of the cells was dead and the other was at greatly reduced capacity.
I have a theory that the AGM batteries when dropped or otherwise mishandled, tend to jamb the internals together causing an internal short. the excessive current in the short causes high internal heat which bulges out the side and causes some leakage. One thing I look for in one of these batteries is obvious damage to the case. About 99% of the time I find one corner flattened, or deep marks where the battery has fallen on something or a lot of floor debris jammed into the case. All of these indicate a drop at some point. As Doc has pointed out, these batteries normally can be used in any orientation. In high current conditions and during charging, I recommend that the battery be mounted in the upright position.