What is the gray circle Finder shows next to a file, that is not a tag?
Thanks for clarifying the question about the location and your OS. 

In your case, the grey dot is a progress indicator for a downloaded file. It used to be a horizontal bar, filling up as the download progresses. Now it's a circle filling up clockwise. 

Sometimes, the circle does not disappear, like in your case, indicating an incomplete download. 

IMO, it is not directly an application problem, since I have seen this behaviour in Google Chrome as well as Opera and Safari. There was a report here on SE about this being a bug in Chrome (see here), but in the comments, you see other users had had it happened in other apps as well.

Since the file still opens, it seems to be a finder refresh problem for which there are several solutions. 


The easiest would be to wait (not clear how long) for it to disappear (like in your case).
Try restarting the app with which you downloaded the file, in your case Google Chrome.
You could try forcing a refresh of the finder window by changing the directory, e.g. by moving up or downward a level or closing and reopening the finder window. 
You could logout of your profile and login again (a bit too much IMO).
There is a similar problem with the finder dock and recommendations are to kill the dock via a terminal command (again look here on SE in the comments). You could do something similar with the finder, but I would not recommend it.


I hope it clarifies this problem a bit.