I recall dripping onto the grip magwell area... I removed the grips and whewwwww.... all good.
I too fall into the corrosive category and can eat alum framed glasses.
my guess, hand sweat got underneath the slide stop and thumb safety even though it had a large accumulation of EWL there, my corrosiveness got it.
Luckily those areas are hidden underneath those parts.
I have some old Militec and doing the heating process on the exterior surfaces in hopes to minimize future issues.