If you give your Toolbar Tooltips, run your app, then hover over those Toolbar Items the tips appear as expected as you move on and off an item. BUT if you rest on one item for a while (1-2 seconds) then hover immediately onto another item (ie don’t hover off the Toolbar), the same tip repeats on every Toolbar Item.
This behaviour does not happen on macOS. I haven’t tested Linux. Can someone please verify it isn’t just me and I’ll add a Feedback report.