I don't understand why this Mac client was at all if pasting text does not work properly. At least with Version 6.1 (452115 Direct) pasting text from clipboard does not function properly (I paste link from Safari, but my experience is it happens with many different sources)
After pasting: I do not understand how two line breaks between "Układy kwantowe:" and "Quantum... " get deleted. It does not seem related with interpreting the pasted contents, but pasting seems to modify text nonlocally. Are some formatting tags from the copied text inserted into text?