Moving files, on the client or server side, without forcing everything to re-sync

I’ve had this happen a number of times, so I’d like to avoid it moving forward. I’ll give you an example:

I have a second drive in my computer, internal or external, with a bunch of music on it. The drive starts to get old, and I decide it’s time to replace it. So I copy all my MP3s from the old drive to the new one, unmount the old drive, and mount the new one where the old one was. So far, so good: Nextcloud detects the directory just as it did before.

Here’s the problem: in every case, Nextcloud will immediately start overwriting all my local files with the ones on the server. This isn’t the end of the world, but the reason I manually copied my files was so that I wouldn’t have to download them all over again.

At first I thought this had to do with mismatched partition types, but it happens even when the old and new folders are on ext4 partitions (my server is also ext4—even the external storage).

I will also point out that in the case I described, the server-side files are accessible through Nextcloud as external storage (it’s an external drive). I don’t know if that matters.

Right now, I’m getting ready to replace the external storage on the server side (I run self-hosted Nextcloud on my LAN). I’m worried that when I disconnect the old drive, and mount the new one in the same place, I’m going to have the same problem where a ton of stuff is going to get transferred.

Could this be related to missing, hidden files? If I make sure all the dotfiles transfer to the new media, will this solve the problem? Or is it something else?