A fix has now been implemented on platforms Mac and PC. If this has affected your account, you will need to send in a support inquiry .
We have received reports that when selecting other challenges, partial or full completion on any challenge may unlock. Current challenge selected will progress as expected.
Our dev team is looking into this issue now, and we expect to have a fix for this soon. If you have experienced this, please send in a support inquiry.
We will edit this post with any updates as we get them.
Thank you for your patience!