Fixed and released in our 2021 summer update, more details here https://www.youtube.com/watch?v=_oc0AevNRv4

Same here. I just analyzed 8 symbols and used lines and scribble. I went away for some hours leaving the browser running. When I came back and went through the list for 7 of the 8 symbols my drawings were gone. Only the last symbol still had the drawings.

A lot of effort wasted. Happens to me regularly. Very annoying.

same here. very annoying. please fix !