Insert Bug version 4.0.3.4

I'm using version 4.0.3.4 on windows 7 x 64 LibreOffice Calc

When I'm clicking a cell and then move the cursor into the text field of the
formula editor seting the cursor anywhere in existing text (in my case after
I copy pasted in, dunno about that's relevant) after shifting the cursor to
behind the last letter after activated the insert key and then moving with
the arrow keys the cursor in frotn of the last letter whilest the insert
functionallty is still active and now pressing any character the behaving in
the formular editor text is as expected. But after confirming this, the
confirmed text does differ. as if I review the submitted column everywhere I
used the insert the letteres weren't repalced, isntead they got merged.

Can someone confirm this?