The issue

Pressing the up arrow key while your selection is on the first child block of another block should navigate to the parent block. At some point this behavior seems to have been broken and no longer works properly in master. This was working properly in Gutenberg 7.0.0.

I suspect this issue may be related to #18780 and #18881.

How to reproduce

1. Create a new post.
2. Insert a Group block.
3. Insert any block inside the Group block.
4. Press the up arrow key. Notice that you don't navigate to the Group block.
5. Press the up arrow key again. Notice that you navigate to the post title, skipping the Group block entirely.

Environment

• WordPress 5.4-alpha-46814
• Gutenberg master as of 49dac29
• Using Dissenter browser 0.70 (based on Chromium 78)