Thanks for your question. I have tried to reproduce your issue on my system but I am having trouble recreating the steps you are using to “copy and paste a batch of URLS“. Are you referring to the “File URL” column in the Media/Assistant admin submenu table? If so, can you post step-by-step instructions on how to select and copy more than one URL at a time? Any additional details you can provide will be helpful.
If this is a high-volume or recurring need, you might consider the excellent Admin Columns Pro plugin, which has a very robust facility to export data form the Media/Assistant table to CSV files.
Thanks for your interest in the MLA plugin.