Need to re-convert RTF(D) items after editing in NisusWriterPro: normal behaviour?

DevonThink 3.7.2 Catalina latest version
I noticed that if I edit a DevonThink RTF(D) item in NisusWriterPro (for example I prefer NisusWriterPro tables) → save → return to DevonThink, I am unable to edit the RTF with DevonThink’s editor (behaves as if the item is locked).
To do so I must reconvert the item to RTF via Data → convert to RTF.
Please note that the editing is very basic, usually only adding a small table.
thank you

This sort of thing has been discussed before, as a search on “Nisus” reveals.



I will look. Thank you