Duplicate Unwanted / Unintentional marks

[Masetrix]

Affected version

2.1.3

If I have written a longer text and only wants to mark one word or one line bold,
Sporadically, other unmarked lines are marked in bold.

Affected: XF 2.1.3 - wysiwyg editormode (FF 60.8.0esr (64-Bit))

reproduce:
Write some text... mark some Text as bold, toggle BB code and back...

 

[Ozzy47]

Pretty sure that is the same as this, https://xenforo.com/community/threa...atting-not-only-to-selected-paragraph.167733/

 

[Masetrix]

Pretty sure that is the same as this

Confirmed. With Crome the error does not occur.
Oh ****. Now even Firefox becomes unusable ...