Thank you for writing back.
I also tested on Windows 10 and the text was pasted properly. It appears that the issue might be caused by the string itself stored in the clipboard. We have no special logic handling the non-ASCII characters.
Can you please try and paste the text into notepad first and then copy and paste it to the grid. You can also try typing the text in the cells and see if the issue would persist.
I hope this helps. Should you have further questions please do not hesitate to write back.