The toolbar behavior in the "Reusable Blocks" is buggy.

[ddryo]

When editing "Reusable Blocks", if you focus on "Reusable Blocks" itself after focusing on the blocks inside, the "block toolbar" will jump to "Reusable Blocks".

Screenshots

Editor version

• WordPress version: 5.4.1
• Gutenberg plugin version : 8.2.1

Note: It also occurs in WordPress 5.4.1 without Gutenberg plugin.

Desktop (please complete the following information):

• OS: macOS Catalina
• Browser : Chrome, Safari

Additional context
When there are multiple blocks inside, I can edit it by somehow moving the focus to another block.

[ddryo]

It was more serious when in "Top toolbar" mode.

In this case, the toolbars for the blocks in "Reusable Blocks" were not available at all.

[draganescu]

I was able to reproduce this.

[shaunandrews]

I’ve seen similar things happen with the Navigation block nested within a Group block.

[chrisvanpatten]

This is a duplicate/relates to #19436 and #18560. It would also be solved by #23601, which is blocked by #22639.