@daria19 I did just recognise that it is not the banner (only), but actually the GMX website in general, when accessing from here: https://millionenklick.gmx.net/
When I am at this page, not login or anything, and just click at the "GMX" logo at the top left of the page, a link to plain https://www.gmx.net/, it crashes.
Platform is Windows 11, a portable instance of Opera developer.
Regarding crash report uploads: yes, uploads are done/repeated every time until now. I generally have the impression that some of the settings I do are not permanently stored. It might be related to the structural changes of Opera profile data, where vast parts where shifted into a "Default" sub directory. E.g. also permissions to access camera, microphone, platform notifications etc, are not stored permanently. Camera and microphone access sometimes gets refused in the middle of a WebRTC video session, so that I need to reload the page and grant access again.