My note in the update log was mostly for people who have a second version installed in their mods folder. Normally steam should automatically replace old versions in the contents folder after an update. I've had messages like that popup if I tried to delete/reinstall something that I already had open (usual a stray file I was looking at) but didn't realize. Other times my antivirus program was blocking a downloaded file for some reason. But this is probably not either of those :/ I would try running the steam program itself as an admin, if you haven't already, then while running it verify the integrity of civ VI's files and then resubscribing. If steam continues to not download the mod, manually download and install it from here (stuff placed in the mods folder should overwrite the workshop's content folder). There are also file unlocker programs that can delete files being blocked by a unknown process. It's been a while since I used one, so I'm not sure which are reputable to recommend. I'll continue to research the issue to see if I can learn anything else.