I was also experiencing random disappearing of drawings on Friday, but also I have been having for the past week or two and it's is still happening now. The drawing tool is not attaching to the chart on the final click of drawing. I have to refresh the browser each time after changing the time interval of the chart then it works until the next time change the time interval. It appears to be the same on Chrome and Microsoft edge.
Is anybody experiencing this and is there any solutions out there?