SUMMARY
In dolphin context menu for files, there is a 'share' menu which exposes options like Email, Bluetooth and KDE Connect. On selecting some of them, another window pops up asking for more details (e.g Send via Bluetooth shows bluetooth devices and Send to Device shows KDE Connect pair devices).

But with recent update (confirmed on version 24.05 on fedora kde stable and also 24.11.70 on Neon unstable), those options only work once per instance (i.e window) of dolphin. Once an option is selected, none of the share target items function for any file when triggered from the same dolphin window. Opening a new window, and sharing a file, it works again, but 1st time only.

STEPS TO REPRODUCE
1. Open a dolphin window, select some file.
2. Right click> share> select, say, kde connect option (Send To Device)
3. Another 'Send file - dolphin' window appears to select devices, either send the file or just close the window
4. Try to repeat from step 2, either for the same file or a different one.
5. Try different combinations, say first select share> Send via Bluetooth and then subsequently try KDE Connect option. Or try the same option twice for a file.  

OBSERVED RESULT
Sharing something again should show 'Send file - dolphin' window again (or launch email client or nextcloud window or whatever depending on selection).

EXPECTED RESULT
None of the share items work once one is selected for a file. It again works on a new window of dolphin, but only one time for that window.

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 40
KDE Plasma Version: 6.1.3
KDE Frameworks Version: 6.4.0
Qt Version: 6.7.2
Kernel Version: 6.9.12-200.fc40.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-6300U CPU @ 2.40GHz
Memory: 11.1 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 520
Manufacturer: HP
Product Name: HP ProBook 640 G2

ADDITIONAL INFORMATION
I also tried this in the latest neon unstable build (neon-unstable-20240807-1052.iso) with dolphin version 24.11.70, and it's largely the same issue. The only other quirk I found was, when email option was selected, it showed a red banner complaining that no email client was found (expected). Trying to share something else within that dolphin window, it started showing the red banner about no email client, regardless of which option I selected (bluetooth/kdeconnect/nextcloud etc.) as if all those options were trying to launch email client.

I can't confirm this for my fedora installations as I've thunderbird setup and sharing via email doesn't do anything (another bug? thunderbird is flatpak if that's relevant).