Is there any significant changes for the mapbubbles in tilemap chart since version 9? I can't find any in the documentation. I tried creating a simple fiddle and the issue is present there.
This is how it looked like in version 8.1.2

With version 9.3.0 to latest version, this is how it looks

Here is a link to the fiddle https://jsfiddle.net/sagarv/cdw30neo/9/