Upgraded my Kinoite media center PC to 40 and discovered the previously working Kodi flatpak from flathub would crash with a floating point exception when attempting to play a video.
Reverting to 39 restored functionality.
My best guess is that it is related to this pipewire issue: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/3995 which was apparently fixed a week ago upstream.
This should be filed as a bug for pipewire in bugzilla. It will likely be fixed once an update with the fix lands in Fedora 40.
Had a change to attempt to upgrade to 40 again today. No improvement.
New information: It doesn't appear to be related to the pipewire bug. Problem also affects VLC, and doesn't appear to affect local playback, only over SMB. Nearest I can figure from finding a few other scattered reports across the internet it has to do with Plasma 6 and kio-fuse, but other than potentially hacking around it by modifying .desktop files to remove smb from the X-KDE-Protocols list there's really not much information. I'm guessing there's been a regression of some sort.
Anyway, if that is accurate (and I haven't had a chance to test it since that involves multiple reboots on a device I'd rather be, you know, actually using) this is a KDE problem, so I'll see about reporting a bug there.
Ugh, ok, this was two separate issues. The VLC issue seems to be as described, but the Kodi issue is a problem with Plasma 6 and the "sync playback to display" and had nothing to do with SMB. Simply disabling that setting allows kodi to work normally again.
Metadata Update from @tgschultz: - Issue close_status updated to: Deferred to upstream - Issue status updated to: Closed (was: Open)