In some situations, duplicate files can appear on OneDrive: one with the the original file name, and a duplicate with the same file name with the PC name appended.
OneDrive creates a file with the computer name appended whenever a conflict is detected. For instance, if you have a file named "MyFile.txt", OneDrive will create "MyFile-ComputerName.txt" in a conflict situation.
A conflict exists when the file has been updated in more than one place and the OneDrive Sync software is unable to merge both versions of the file. OneDrive Sync creates a new file with the computer name added to the end as a way to distinguish which files have been changed and from which location.
An easy example is with a computer that's not connected to the internet. If you update "MyFile.txt" on the laptop, the file won't sync right away (because there's no network connection). If you also update "MyFile.txt" on your desktop, when the computer connects to the internet, you'll have a conflict, because the file was updated in two places. As a result, OneDrive creates the conflict copy.