Each of the dna companies at some point has revised or changed the formulas to determine who they choose to show you as a match...and lots of people have experienced having people match you at one company who aren't match at one of the other companies. That's why it is useful to upload to gedmatch or transfer your test to ftdna so you can see where and how large dna segments are with matches there.

The circles seem to be helpful to some people, but there are lots of questions re why some have circles and others don't...I wouldn't worry too much yet if a circle hasn't yet showed up re a particular ancestor