Google Charts tooltip flickering
Yes, it's a little bug.
You only need to add this to your CSS:
svg > g > g:last-child { pointer-events: none }
Yes it appears that flickering is an open issue.
https://github.com/google/google-visualization-issues/issues/2162
That works in my case
svg > g:last-child > g:last-child { pointer-events: none }div.google-visualization-tooltip { pointer-events: none }