Thanks for the reply! That is one of the sites I found while googling, I tried the various different things it suggested and didn't get anywhere. I'm running the same version of Windows as you are, Win 10 Pro-64bit (1809) (I posted it in the original post, guess you didn't see it).
I'm using a mapped drive for my different shares.
I don't know what I did but I tried to copy another file to a different folder on the share and boom it worked. Went back and tried to move the original file that was giving problems and boom, that worked as well. Now I'm having no issues at all with copying files. I have no idea what I did to fix the issue, but it works now.
Thanks again for the reply, if I figure out what fixed the issue I'll be sure to post it here.