Jeff Liebermann wrote:
I'll see if I can find some details on the chemistry of such
electrolyte deterioration.

I first heard about this from an engineer friend who worked in the
(automotive and marine) lead acid battery industry. I was grumping
about the failure of my alarm panel's gel cel after only four years -
with perhaps only one discharge / charge cycle during that time, and he
told me that it was because the electrolyte that "became neutralized"
(his words). I didn't think to challenge him at the time.

Let us know what you find out.