I'm on EndeavourOS using BTRFS, with all the latest updates installed. When I installed and rebooted I noticed that for any folder on a network drive, the folder previews have just stopped working. Local folders work just fine, which made me think it was just that option in the preview settings menu but that hasn't been changed. As well, the actual image and video previews on network drives still work, it's JUST the folder previews that don't. The network drives in question are being shared from a windows 10 computer and are mounted with full rw permissions. Also in case it wasn't clear, I am using dolphin.

I've never had a problem with this setup in the past, it worked just fine before the update and restoring a snapshot from before the update confirms that. No settings I've tried in Dolphin has fixed it, I've tried reinstalling dolphin, restoring all the settings to defaults, nothing seems to want to work.

I can give more details about my setup itself if required, but like I said, there was no issue before doing the latest batch of updates so I'm just assuming it was something in that? If there's any suggestions or fixes I can try in the meanwhile I'd love to get things sorted out. Not having folder previews makes managing all my photos nearly impossible lol.

Here's a list of all the updates that I had installed if it helps. I update pretty frequently so having a longer list is kinda rare.

https://pastebin.com/n4G74knD

I don't have a solution for you, but I can confirm that I am having the exact same problem after the recent update to Plasma 5.24.

All of the folder previews for network shares from my NAS no longer appear within Dolphin, they just appear as plain folders without previews. All of the remote files themselves still having working previews, and local folders still have working folder previews as well, it is just the network share folders that have this issue. Prior to the update to plasma 5.24, the folder previews worked perfectly on my end. I have tried basic troubleshooting measures (restarting, deselecting folder previews in Dolphin settings and selecting them again, changing the file size limit for remote previews to 0 and back again) but nothing had any effect.

I am seeing this issue on all of my desktop systems (all running fully up to date Arch Linux), and my NAS shares are via NFS from a Ubuntu server.

EDIT: I created a bug for this issue: https://bugs.kde.org/show_bug.cgi?id=450482

I am having this issue with volumes formatted as NTFS or exFAT. It is working fine on the partition where my operating system is installed. All the folders there are displaying previews in Dolphin. However, it is not working for my other disks that are NTFS or exFAT formatted. To test it, I formatted a flash drive with NTFS and placed a folder of pictures on it. The folder has no preview when I view it with Dolphin. I also tried with an external hard drive formatted as exFAT and it did not display any folder previews. Then I deleted the partition and made a FAT32 partition and placed a folder of pictures there. It is previewing just fine.