I think @rosiecar is right here.
However my “Current earnings this month (estimated)” should be 6.6975-6.4625=0.235 BAT. But it has reset to absolute zero (I got few ads today).
So the catch here is, accumulated payment tokens (BATs earned) are periodically sent by browser to the rewards server. Sometimes after few hours, sometimes after few days (can be 7 days also). And I think time allotted is generally random (may be by the server or browser itself).
This means that some payment tokens (about 0.6 BAT in the case of @EvilxSeal and 0.235 BAT in mine) have not yet been sent to the rewards server by the browser. So I expect it to correct itself in some time for @EvilxSeal and at 8:46:46 PM today (in 10 hrs) for me. I will Update.
Also I think something has to be done about showing past month’s earning as arriving, even for a brief period of time. Since it might not be a Bug but expected to work this way.