Semantics means "meaning". Meaning is important.
To you it might be all the same -- "stuff doesn't work" -- but to me, I have to know what I'm chasing.
System settings -> battery does show per-application stats, and it's built-in, no need for a third party app. If you see Aqua there, and with a large percentage, then that's something.
On the other hand, a sudden drop in overall battery charge does not tell me much -- and as I already mentioned, there are over 200 users who reported this issue just in the Android bug tracker, linked above. I'm positive that not every single one of them uses AquaMail.
Not questioning what you're seeing, it's just that when there is a system level issue, a perfectly valid code sequence in an application (mine or someone else's) may have unfortunate consequences. I'm sure you understand my logic here.
A debug log? Sure, why not, if you can make one and actually capture the issue there.