Try changing MySQL upload to every Full 5 minutes. Every 15 seconds is a bit much. I don't know if that is the problem. But from the screenshots you showed that is the only difference between yours and mine.
Every Full 5 minutes makes it upload predictably every 5 minutes on the exact 5 minute marks of 00, 05, 10, 15, 20, 25....etc.
Paste your MySQL Query here to inspect that.