I think that's a byte order mark, aka BOM. That means the csv file is utf-8 encoded. That could well be since afaik Qlikview exports csv files in utf-8 encoding. If you view the file in something that thinks the file is ascii you can get the funny characters. In editors like notepad++ you can change the encoding to ascii and then save the file.
Hi Gysbert. This is happening to me on Qlik Sense as well. I've tried what you said but still have the same problem. Is very weird because it's not happening always, and it seems that the size of the data is not related to the issue. I'm thinking that it might be something on related to the sintax of the Store but not sure though. Any ideas on how to solve this?