I have purchased 2 Kingston microSD XC Class 10 64 GB card. Both automatically became write protected. By no means I could remove the write protection. Ulitmately had to send one of the cards for replacement after performing low level format to erase all data.
For the second card, low level did not work. Hence have not send it for replacement.
Also, note that replacement process takes easily a month for 64 GB microSD XC Class 10 card.