.part issue When saving to external drive through SFTP, multiple .part files are saved along with final file

When uploading to external drive through SFTP huge quantities of .part files are created depending on file size but they do not get erased after file is uploaded. If I upload a file directly using a ftp client to this location it’s fine but through nextcloud it does this. My nextcloud is hosted on a shared server and was installed through the cpanel. Running 15.0.2 and the external drive is running on a windows server. I am new to nextcloud and have installed it last week and testing it out. Looked for answers but could not find any. Any help would be appreciated. Thank you