Incorrect vertical alignment for popover for some JP blocks when using Gutenberg 8.5.1

[fullofcaffeine]

Steps to reproduce the issue

1. Access a simple or AT site with Gutenberg 8.5.1;
2. Add a new post to bring up the block editor;
3. Add the jetpack/tiled-gallery, jetpack/subscriptions, gif to to it;
4. Also, add the jetpack/videopress to the editor. The toolbar aligns correctly for this one so we'll use it to compare against the problematic ones;
5. Make sure the browser viewport is wide enough for the popover toolbar to appear floating and not as a docked toolbar the top;
6. Click each of the blocks on the page to select them, observe how the first three added don't have the toolbar properly aligned in comparison with the jetpack/videopress.

What I expected

The popover toolbar to be properly aligned vertically to the block

What happened instead

The popover toolbar is not aligned to the block vertically to the block

Screenshots

Expected	Actual (for some blocks)

[kwight]

This isn't an issue for the Subscriptions block any more, but is still visible on the GIF and Tiled Gallery blocks.