This bug is definitely fixed for me since Windows 10 Creators Update.

I have 4 ssds in my computer.

I can now do a standard copy & paste of a folder ( that is marked with any of my customized...

This has been annoying me too !
There is this other topic about it on Windows TenForums, posted 22 Aug,
Permanent Custom Folder Icon Problem

But -
1 quick way I found to copy and paste to...