A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
Running OneNote 2016 on Win 10, after the update yesterday, I noticed no ink loss after disabling handwriting recognition.
After turning handwriting recognition back on, the problem of disappearing ink returned.
After again disabling handwriting recognition, the problem no longer recurs.
I hope that helps you to find out where the problem lies. I am just glad that I can take notes now, since I do not rely on the automatic handwriting recognition.