TL;DR: The Data Import feature requires the next datetimestamp in the sheet/csv to be newer than the one before it, and that's not cool.
Alright, I believe I've found, in my opinion, a less-than-desirable behavior in the data import feature. I stumbled upon it while importing data from an old instance of Mango where for some reason it wouldn't show me "chart" info, and therefore wouldn't give me the option to download the data.
So naturally, I clicked on "Show xxx most recent records," and copied and pasted it into a spreadsheet that matched the format of a normal export.
I spent HOURS wondering what I had done wrong, for every time I imported, it would show me
Point values to be written 7218
Or some such nonsense. And it would NEVER go away until I rebooted. So, after much gnashing of teeth, I actually found one or two imports here and there among the objects I was trying to import from, and realized that sometimes it was importing the FIRST value listed, but not others. BUT WHY!?
The dates were from newest->oldest, not oldest->newest. Now, call me crazy, but if each line is individually evaluated, there should be no reason you can't import with ANY time in ANY cell order, but there it is. It seems to me that the Data Import will ONLY import data if the next date in the list is NEWER than the last, which makes absolutely no sense to me.
I have already imported all necessary data as of this moment, but I figured y'all might want to either fix it or maybe someone else has this issue and they can find the solution here.