Tooltip Not Working - BUG in the PBI Service ?

Here's an issue where Desktop is behaving differently than the PBI Service. Quite simply, I've created a report with a line and column chart. In Desktop, when I hover over the line, the tooltip appears. When I publish the report to the PBI Service, it does not.

I've attached a report using the provided sample data set and created a visual where bars appear intermittently. Hovering over the bars works fine. But if I hover over the line where there's no bar, the tooltip appears in Desktop but stops appearing when I publish to the Service. I've tested this in the latest versions of Chrome, Edge and Firefox, and I've confirmed the experience is consistent with other users on other devices. 

Any thoughts? Here's how it looks in Desktop and this is the desired behavior. 

Link to PBIX file: 

https://www.icloud.com/iclouddrive/0a8RQWkEDigbx5uGDhy3foqBA#TooltiipTest