🇬🇧United Kingdom @ded

We are having this issue also with 3.0.0-beta1. Our console error is slightly different:

TypeError: Cannot destructure property 'parent' of 'selection.getFirstPosition(...)' as it is null.
    at getClosestSelectedIframeEmbedWidget (iframeEmbedUtils.js:78:11)
    at Object.getRelatedElement (iframeEmbedToolbar.js:78:102)
    at q._updateToolbarsVisibility (ckeditor5-dll.js?v=41.3.1:5:718206)
    at r.<anonymous> (ckeditor5-dll.js?v=41.3.1:5:717231)
    at r.fire (ckeditor5-dll.js?v=41.3.1:5:663135)
    at r.update (ckeditor5-dll.js?v=41.3.1:5:602960)
    at Object.fire (ckeditor5-dll.js?v=41.3.1:5:663135)
    at de (ckeditor5-dll.js?v=41.3.1:5:201940)
    at pe.fire (ckeditor5-dll.js?v=41.3.1:5:201331)
    at St.<anonymous> (ckeditor5-dll.js?v=41.3.1:5:255790)

ded → created an issue.

I've hit a similar issue with a profile element nested in a Tab. Unfortunately, the patch doesn't work.