I see the same notification. When a video starts on the desktop, which includes auto-playing, no-audio previews which are frequent on social media sites, a notification is sent to the phone, which then sends a notification back to the desktop. That last trip results in the Ongoing Media Activity notification.

Operating System: KDE neon 6.3
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.13.0
Qt Version: 6.8.3
Kernel Version: 6.11.0-24-generic (64-bit)
Graphics Platform: Wayland
Processors: 22 × Intel® Core™ Ultra 7 155H
Memory: 30.8 GiB of RAM
Graphics Processor 1: Intel® Arc
Graphics Processor 2: NVIDIA GeForce RTX 4060 Laptop GPU
Manufacturer: Dell Inc.
Product Name: Inspiron 16 Plus 7640

Created attachment 180652 [details]
"MediaOngoingActivity" notification

I also have this issue after upgrading my phone to Android 15, Samsung One UI 7.

The notifications is triggered whenever I start any media playback on my laptop.
Can reliably reproduce with Spotify, VLC, and YouTube. 

Operating System: Kubuntu 25.04
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.3
Kernel Version: 6.14.0-15-generic (64-bit)
Graphics Platform: Wayland
Processors: 20 × 13th Gen Intel® Core™ i9-13905H
Memory: 62.5 GiB of RAM
Graphics Processor 1: Intel® Iris® Xe Graphics
Graphics Processor 2: NVIDIA GeForce RTX 4070 Laptop GPU
Manufacturer: LENOVO
Product Name: 83BY
System Version: Yoga Pro 9 16IRP8

Same for me. Even mousing over a Youtube thumbnail in the browser will trigger it. Seems like it just needs to be blacklisted/ignored.

I'm also experiencing this issue

DESKTOP:
Operating System: Arch Linux 
KDE Plasma Version: 6.4.1
KDE Frameworks Version: 6.15.0
Qt Version: 6.9.1
Kernel Version: 6.15.3-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 2600 Six-Core Processor
Memory: 32 GiB of RAM (31.3 GiB usable)
Graphics Processor: NVIDIA GeForce GTX 1660

PHONE:
One UI version: 7.0
Android version: 15
kdeconnect version: 1.33.4

So, now what? Does really no KDE Connect dev has a Samsung device? Can we help somehow to fix this annoying notification?

(In reply to Maximilian Böhm from comment #6)
> So, now what? Does really no KDE Connect dev has a Samsung device? Can we
> help somehow to fix this annoying notification?

There was discussion on something related to this, it's a band-aid fix, but one way is to install an app called [TidyPanel](https://play.google.com/store/apps/details?id=com.dharmapoudel.tidypanel) and hide notifications with the title "MediaOngoingActivity".

Confirming because the issue affects multiple users

I confirm the problem on the Galaxy S4 Ultra (Android 15, with the latest updates), I can also confirm that a third-party solution generally solves the problem, but I would like to eliminate the cause and not use a third-party solution.

Quote:
"There was discussion on something related to this, it's a band-aid fix, but one way is to install an app called [TidyPanel] (https://play.google.com/store/apps/details?id=com.dharmapoudel.tidypanel) and hide notifications with the title "MediaOngoingActivity"."

Kubuntu 25.04 [kde plasma 6.3.4] + kdeconnect 24.12.3 
galaxy s24 ultra [android 15] + kdeconnect 1.33.4.

There is workaround!!! Just open kdeConnect app on phone go to plugin settings->sending notifications. Now you are in notification filters. Search for something similar to "system UI" it depends on your system language. Then uncheck that app. It will stop sending notifications from that source. I am not sure if there are other notifications from the UI system source.

A possibly relevant merge request was started @ https://invent.kde.org/network/kdeconnect-android/-/merge_requests/556

Git commit 564ba30aef69dbbe435837f01962160843f8ff0a by Albert Vaca Cintora, on behalf of Michał Napiórkowski.
Committed on 08/10/2025 at 11:44.
Pushed by albertvaka into branch 'master'.

Ignore "MediaOngoingActivity" notification

Samsung One UI sends a "MediaOngoingActivity" notification when Media Controls are shown.

M  +11   -4    src/org/kde/kdeconnect/Plugins/NotificationsPlugin/NotificationsPlugin.java

https://invent.kde.org/network/kdeconnect-android/-/commit/564ba30aef69dbbe435837f01962160843f8ff0a

Related bug: Frequent "n notification was received while Do Not Disturb was active" Plasma notification
https://bugs.kde.org/show_bug.cgi?id=513316