@Laz61,
if, as underdog asks, you can take some screenshots and add the steps to the problem report I can/will take it over.
I have in fact also discovered the Credit Note/Invoice problems (a.o.; error with dates, menu item ‘create CN’ visible on a credit note/invoice page itself, ‘invoice’ entries on a CN instead of ‘credit note/invoice’) and made the necessary adjustments in the code and in the templates for this.
FYI. See my forum item here.