Data loss when second user enters entry

[helloiamlukas]

Description

When a second user opens an entry while an other user is editing a bard field, the typed content will disappear and the cursor will focus to the end of the document.

How to reproduce

1. User A opens an entry that includes a bard field
2. The bard field of this entry includes at least two paragraphs/lines
3. User A writes text in the first paragraph/line of the bard field
4. While User A is typing, User B is opening the entry in the browser
5. A part of the typed text of User A will disappear and the focus of the cursor will be at the end of the paragraph/line.

It seems like when the second user enters, an update is broadcasted – but this update still includes the old content.