Thanks for getting in touch.
I notice in your chart you have two y axes, one at the normal position and one at the reverse position. Can you please confirm that when you set the new annotation via the addViewAnnotation method, you are passing in the correct x and y axes which correspond to the data x and y positions of the points, which the heart symbols should overlap? Sometimes an error is made where people can unwittingly pass in the incorrect x or y axis. If a normal and a reverse (in your case y) axis have a similar data range, the annotations can look initially like they are in the correct position. Only when the chart is zoomed does one spot the error. I am wondering if this is the case here.
Can you please confirm that this issue only occurs once you zoom into the chart? Am I to assume that initially, when the chart is first rendered, the heart symbol Views are positioned correctly? Can you please advise if panning from left or right causes the bug which you describe?
We look forward to hearing from you,