Confirmed in test2 and on https://fi.wikipedia.org/wiki/User:Stryn/VE?veaction=edit.

On the page https://fi.wikipedia.org... - there are many Uncaught Error: ve.dm.Document.getBranchNodeFromOffset(): offset 39 is out of bounds etc.

In test2: type four lines of text on four separate lines.

• Add reference to the end of the first line
• add another reference to the end of the second line
• leave the third line as it is
• re-use the first reference and add it to the end of the fourth line

Start highlighting the text and try to delete it with 'Delete' button.
FF displays:
Error: Unbalanced set of replace operations found load.php:316
TypeError: currentNode.children[(nao.offset - 1)] is undefined load.php:479
Error: Unbalanced input passed to document.

After several attempts of highlighting and deleting - the page becomes unresponsive - I can place cursor but cannot move it with arrow or Enter buttons; cannot Save, cannot switch to Read mode(TypeError: data[i] is undefined).