Created attachment 149991 [details]
backtrace

SUMMARY
A home router which redirects dns queries to itself in the event of a loss of connectivity to the ISP, can cause https authentication errors in plasmashell, presumably related to the media control widget or possibly browser integration. The failed url in my case was https://i.ytimg.com/(some_hash_code) , which makes me think it was trying to fetch a thumbnail. I am somewhat puzzled as to why plasma is making requests to Youtube, but it clearly wants an image file for something. The self-signed certificate and/or 401 response from the router results in a warning dialog being presented to the user. Upon canceling or closing this dialog window, the crash occurs and the desktop restarts. The X session appears to remain intact, and all open processes and windows seem to be preserved, it's just the launcher bar and desktop itself that has to reload.

STEPS TO REPRODUCE
1. Connect the system to a network behind a router or other gateway device.
2. Make sure plasma-browser-integration is installed.
3. Open a browser, go to youtube and start playing a video.
4. While video is playing, disconnect or otherwise disable the WAN link on the router, and start redirecting all dns queries to the router or other host which will respond to https requests with a self signed certificate. A common Netgear home router seems to accomplish this.
5. Wait about 5 minutes. It may be possible to trigger a fetch by locking the session or clicking the media player controls applet, but for me this was a time-based repeating occurrence.
6. When the inevitable warning about self signed certificates pops up, click cancel. 

OBSERVED RESULT
plasmashell has a segfault and restarts the desktop

EXPECTED RESULT
quietly close dialog and proceed with life

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.24.5
KDE Frameworks Version: 5.95.0
Qt Version: 5.15.4
Kernel Version: 5.18.3-zen1-1-zen (64-bit)
Graphics Platform: X11
Processors: 24 × AMD Ryzen 9 3900X 12-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 2060/PCIe/SSE2

ADDITIONAL INFORMATION