Curation Rewards Not Being Added To Account!

Currently I upvote about twenty or so posting daily, some of these posting doesn't go anywhere, this I understand, but one or two will climb into the thousands of dollars category.

Tracking my upvotes, sometimes I noticed after a few hours the blue circle that indicates upvoted will disappear, other times the blue circle will remains up to payout. After a period of time passes, I looked to see what my curation rewards is and it doesn't change. Checking my curation rewards history also show that nothing had been added to my account for some two or three days.

So what is happening?

Is there a problem with the Blockchain?

Can someone explain!