Yes, searching for the word "abstract" in my Paperpile database produces dozens of examples like this. These are the most recent examples of papers I've imported where this has happened:
In the first case, I can see that the publisher has included the word "Abstract" at the beginning of the abstract field in the RIS file, so its understandable that Paperpile imports that. In the other two cases, the abstract is not included in the RIS file. In the second case, the word ABSTRACT is included in capital letters in the Paperpile field, as it appears on the webpage for that paper.
As I said, this is only a very minor niggle, and I do see that there would be a problem when the abstract legitimately begins with the word "Abstract". I guess that it would be possible to test whether "Abstract" is followed either by an upper-case letter or by a space and then an upper-case letter, and to remove it in either of those situations...