Problem with JCE Editor in Article -> Group X

[felixmodrow]

I'm using Seblod 4.3.4 on a client website.

View: https://www.allefreiheit.de/errorlog/mks_error.jpg

There I have a Group X (Article) with an Editorfield (JCE) in the backend.

If I add an new Group X Item (+ Button -> 1)
the content from the editorfield before (2)
is incorrectly copied into the new editorfield (3)
of the new Group X item if I saved the article. (This not happends with the TinyMCE Editor)

If I give the field a "Standard Value": XXX" this will be shown at first but then overwritten at the first save.
Only after this it's possible to write in data without be overwritten on the next save button event.

I hope you have a solution.