First of all, I trust this sponsor, I work with them for years.
But recently I see some strange things in my stats.
I started monitoring my stats a few days ago and made enough
screenshots to catch those weird things.
What can it be? Glitches in NATS? Wrong settings on sponsor's
servers on in my account? Anything else?
I can post more screenshots, but these are most demonstrative:

I have sent 3,379 uniques on aug-30.

A bit later I see that it was not 3,379 but 2,824;
the latter amount was reported thru entire aug-31.

Sep-01 already, still the same 2,824 uniques for aug-30.

Now - magic! - it's back to 3,379 uniques for aug-30.
How it's possible that for a long period (more than 24 hours) NATS reported wrong stats?
I have other examples (screenshots) with numbers going up and down, but not for so long.
I keep monitoring, but I would like to hear opinions on this stuff.